Things that will and won't kill your fish

Sk8r · 12/18/2016, 04:22 PM

THINGS THAT WILL
eunicid worms (head has distinct tentacles)
crabs---(any crab with a large claw)
ich (is a parasite, operating much like fleas) and is not 'caused' by anything but its natural reproductive cycle. If it gets into your sandbed, 72 days of no fish is your treatment for the tank.

uronema marinum---particularly on chromis---red ulcers and white film: a disease. Add in brook, most found on clownfish; and flukes; all this is why you quarantine these wildcaught fish who've been through too much togetherness during the collection and sales process.

low alkalinity. Keep it between 7.9 and 9.0, generally. If your alkalinity drops and can't be raised, your magnesium level is low. This isn't in itself fatal, but leads to loss of slime coat and vulnerability to disease and parasites the fish might have resisted.

low oxygen: any time your fish are near the surface persistently, oxygen levels should be a thought. Providers of oxygen: your skimmer, particularly a good one; your return pump, particularly if the water has to fall, causing bubbles; cheato moss in the sump; and an ADEQUATE, surface-stirring agitation---aim a powerhead at the water surface, for one thing.

venomous or spike-armed roommates, especially if the tank is too small. In this case stress IS the culprit---on the armed roommate, who will lash out in distress and lower the tank population.

stray current: a cracked heater or other electric device sending current through the water. Leaves no mark: otherwise healthy fish die.

some snails: if you have fish that sleep in the sand and you black out the tank completely, they may eat the fish alive. Nassarius are particularly bad about this. The takeaway is---don't black out your tank.

Coral-banded shrimp and green serpent stars, also sally lightfoot crabs may take after fish, particularly those that sleep on or in the sand, or that move slowly. Fuzzy large mushrooms can also kill fish by suffocation: they close up like anemones.

Too fast a salinity RISE.

A powerout over the capacity of your tank to provide oxygen: warmth is not a concern, but oxygen is. Consider a battery-driven Penn-Plax pump that will aerate automatically if your area is prone to power loss.

Failure to test basic parameters. Not knowing your temperature, salinity, alkalinity is critical. And for stony reefs, clams, etc, that have stony parts, also your calcium and magnesium levels.

A decision to add whiz-bang supplements without testing the levels. In general adding anything BUT alkalinity buffer, and calcium, and magnesium (for a reef) is not a good idea for a novice; and it's generally not a good idea for an expert. Test to know your levels before dosing ANYTHING, and wait 8 hours before testing AFTER dosing.

Too long an acclimation for a shipped fish; or acclimation in general if mishandled: read the sticky.

A nephew who puts a tv remote or toy truck into your tank: run PolyFilter and a bag of carbon in your water stream, and if it's Cheerios, start doing a 30% water change followed in two days by a 20%. That will usually get you out of it. If a guest knocked a martini into your tank, the worst you'll usually get is a bacterial bloom and a lot of skimmate.

These are most of the hazards.
THINGS THAT WON'T [but look scary.]

Things that are often of concern, that WON'T kill your fish:
bristleworms: some fish take a few tries to learn---but the spines do fall off harmlessly after several days.

kalk overdose (rarely harmful)---do check your salinity, however, as it IS fresh water.

4 days starvation: most fish can forage, and if you have to go out of town, either have a sitter you can trust, an AUTOFEEDER, or don't feed. A pity-feeder who does not understand the danger can harm your tank. Also to watch---if you have cranky fish that might take after weaker ones, you need an autofeeder: Eheim makes a real good one, good for flake or pellet and will feed multiple times a day.

a topoff accident: fish can stand a DROP in salinity. To raise it back to normal safely, just topoff with salt water instead of fresh. If you have a reef, there are other considerations, but corals usually just expell 'wrong' water and wait for conditions to improve.

a few days without a skimmer/a week or so without a water change --- because---life, is all.

CindyK · 12/18/2016, 10:18 PM

We need a "like" button

Thanks Sk8r!

schnebbles · 12/19/2016, 04:19 AM

Just what spike arm roommates are you referring to?

billdogg · 12/19/2016, 06:21 AM

Nice list!

If I could, I'd like to add to the bad list -

Knee-jerk reactions to whatever you perceive to be happening. That will almost always lead to even worse problems.

Jscwerve · 12/19/2016, 08:34 AM

Quote:

Originally Posted by schnebbles

Just what spike arm roommates are you referring to?

I'm guessing, but not limited to:

Urchins
Foxface/Rabbitfish
Not spikey, but can eat fish: Anemones

[tang tailspikes can also deliver serious injury. And so can pistol shrimp and mantises. A dartfish that tries to overnight in a pistol shrimp burrow is likely to turn up dead with a red spot midway on its length.---sk8r]

GimpyFin · 12/19/2016, 10:15 AM

Quote:

Originally Posted by Sk8r

A nephew who puts a tv remote or toy truck into your tank: run PolyFilter and a bag of carbon in your water stream, and if it's Cheerios, start doing a 30% water change followed in two days by a 20%. That will usually get you out of it. If a guest knocked a martini into your tank, the worst you'll usually get is a bacterial bloom and a lot of skimmate.

Great list CJ! Although, your fish don't like Cheerios?

gone fishin · 12/19/2016, 10:21 AM

Quote:

Originally Posted by billdogg

Nice list!

If I could, I'd like to add to the bad list -

Knee-jerk reactions to whatever you perceive to be happening. That will almost always lead to even worse problems.

Great list and what Bill said. Also, if I might add do not chase pH this will almost always end badly for a new person.

Sk8r · 12/19/2016, 12:01 PM

Only my koi like Cheerios---but they're in 5000 gallons of water. Nutrient overdose in a small tank can have really bad results real fast---as the tank tries to process, the oxygen-carrying capacity of the water goes down and down. The sad tale of the tank-sitter who says "well, they kept begging so I kept feeding" is why I say---train your tank-sitter and have your food pre-parceled for each day so there can be NO pity-feeding: even better set up dry food in an autofeeder.

The reason the cure is a water change---dilution is the solution to pollution, where it comes to tanks. [It's a saying, not my invention.] The way you open a window to clear the air---clean water helps many situations.

CrayolaViolence · 12/19/2016, 03:22 PM

Do you have any links to documentation/studies about nassarius snails killing healthy fish? Thanks

Sk8r · 12/20/2016, 10:11 AM

Experience, sadly. Caught in the act. Turned the lights on and the poor fish, though alive and waking, was in really sorry shape.

Don't worry about nassarius---they're good snails. Just don't do a total blackout: it's not needed for cyanobacteria treatment: room lights only will do right fine.

Cancun · 12/21/2016, 10:45 PM

Great post Sk8r!!! And all so true! Yea...I also totally agree with billdog too....in my experience when you panic when something is out of whack....things get worse.

Elricsfate · 12/22/2016, 09:02 AM

Thanks Sk8r!

I have a small Sally Lightfoot in my 75. I like the crab, seems interesting. But if it's a danger to other inhabitants I will leave it in the 75 when I move the other inhabitants to the 180. So that brings up the question, what are safe tank mates for these crabs? I'm not maintaining an entire tank for one crab. :-)

Sk8r · 12/22/2016, 11:27 AM

Sally lightfoots grow to about 10-12", and at that rate, eat what they can catch, particularly resting fish. I'd say trade her.

Elricsfate · 12/22/2016, 12:22 PM

WOW!

I have looked them up previously, and liveaquaria.com lists their max size as 3"

That's why I was cool with getting one.

Interestingly, if you Bing Sally Lightfoot you get these pics of a large, red crab. But the one in my tank is small, flat, and brown with stripes like the one that shows up if you search for Sally Lightfoot on LA's site.

Are these two different crabs?

Sk8r · 12/22/2016, 04:31 PM

THey might be. I've seen travel videos of a place swarming with what they call sally lightfoots and it was scary. They may also be limited by tank food availability. But 3" across the shell is still pretty scary size for a tank crab that has fair-sized claws.

Joe0813 · 12/22/2016, 06:16 PM

I thought stray voltage couldn't kill fish?

Sk8r · 12/23/2016, 11:17 AM

It's a complex question: yes, it's current that is harmful; but stray voltage can vary from mild to 'sends a shock to your elbow'. Any contact between electricity and water is not a good situation, which is one reason to be picky about brands of heaters---one of the common sources of problems. And of course, GFI's on all wall sockets used with water: that'll save your equipment, too.

Joe0813 · 12/24/2016, 06:08 PM

i had a few fish die a few months ago that were doing perfectly fine in my tank. then all of a sudden died. I did QT them. found a small GFO pump was zapping my tank... guess I found my answer to what killed my 250 dollar purple tang

j.falk · 03/20/2018, 07:47 PM

Nassarius snails can eat fish? I thought they mainly fed on things in the sand bed.

Sk8r · 03/20/2018, 09:07 PM

If your fish is sleeping on the sandbed they won't discriminate if the dark is total and the fish is deep asleep. This is why turning the lights out is safe, but blacking out the tank to pitch blackness is not. When we say 'lights-out' treatment for cyanobacteria, we mean keep the lights off, don't drape the tank.

Bent · 03/20/2018, 09:44 PM

Mycobacterium marinum and Gram positive infections. Staph, strep and enterococcus. Gram positive infections have >50% mortality rate in fish.

ramseynb · 03/21/2018, 02:08 AM

So keeping alk levels at natural seawater levels is bad for fish? Hmmmm

j.falk · 03/21/2018, 05:31 AM

Quote:

Originally Posted by Sk8r

If your fish is sleeping on the sandbed they won't discriminate if the dark is total and the fish is deep asleep. This is why turning the lights out is safe, but blacking out the tank to pitch blackness is not. When we say 'lights-out' treatment for cyanobacteria, we mean keep the lights off, don't drape the tank.

Now I'm glad my hermits ate all of the ones I had.

Bent · 03/21/2018, 05:53 AM

Quote:

Originally Posted by ramseynb

So keeping alk levels at natural seawater levels is bad for fish? Hmmmm

No, swinging all levels down to sea levels and swinging it back up is.

ramseynb · 03/21/2018, 06:25 AM

Quote:

Originally Posted by Bent

No, swinging all levels down to sea levels and swinging it back up is.

Gotcha. Yeah, that is bad for pretty much everything.

12/18/2016, 04:22 PM	#1
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	Things that will and won't kill your fish THINGS THAT WILL eunicid worms (head has distinct tentacles) crabs---(any crab with a large claw) ich (is a parasite, operating much like fleas) and is not 'caused' by anything but its natural reproductive cycle. If it gets into your sandbed, 72 days of no fish is your treatment for the tank. uronema marinum---particularly on chromis---red ulcers and white film: a disease. Add in brook, most found on clownfish; and flukes; all this is why you quarantine these wildcaught fish who've been through too much togetherness during the collection and sales process. low alkalinity. Keep it between 7.9 and 9.0, generally. If your alkalinity drops and can't be raised, your magnesium level is low. This isn't in itself fatal, but leads to loss of slime coat and vulnerability to disease and parasites the fish might have resisted. low oxygen: any time your fish are near the surface persistently, oxygen levels should be a thought. Providers of oxygen: your skimmer, particularly a good one; your return pump, particularly if the water has to fall, causing bubbles; cheato moss in the sump; and an ADEQUATE, surface-stirring agitation---aim a powerhead at the water surface, for one thing. venomous or spike-armed roommates, especially if the tank is too small. In this case stress IS the culprit---on the armed roommate, who will lash out in distress and lower the tank population. stray current: a cracked heater or other electric device sending current through the water. Leaves no mark: otherwise healthy fish die. some snails: if you have fish that sleep in the sand and you black out the tank completely, they may eat the fish alive. Nassarius are particularly bad about this. The takeaway is---don't black out your tank. Coral-banded shrimp and green serpent stars, also sally lightfoot crabs may take after fish, particularly those that sleep on or in the sand, or that move slowly. Fuzzy large mushrooms can also kill fish by suffocation: they close up like anemones. Too fast a salinity RISE. A powerout over the capacity of your tank to provide oxygen: warmth is not a concern, but oxygen is. Consider a battery-driven Penn-Plax pump that will aerate automatically if your area is prone to power loss. Failure to test basic parameters. Not knowing your temperature, salinity, alkalinity is critical. And for stony reefs, clams, etc, that have stony parts, also your calcium and magnesium levels. A decision to add whiz-bang supplements without testing the levels. In general adding anything BUT alkalinity buffer, and calcium, and magnesium (for a reef) is not a good idea for a novice; and it's generally not a good idea for an expert. Test to know your levels before dosing ANYTHING, and wait 8 hours before testing AFTER dosing. Too long an acclimation for a shipped fish; or acclimation in general if mishandled: read the sticky. A nephew who puts a tv remote or toy truck into your tank: run PolyFilter and a bag of carbon in your water stream, and if it's Cheerios, start doing a 30% water change followed in two days by a 20%. That will usually get you out of it. If a guest knocked a martini into your tank, the worst you'll usually get is a bacterial bloom and a lot of skimmate. These are most of the hazards. THINGS THAT WON'T [but look scary.] Things that are often of concern, that WON'T kill your fish: bristleworms: some fish take a few tries to learn---but the spines do fall off harmlessly after several days. kalk overdose (rarely harmful)---do check your salinity, however, as it IS fresh water. 4 days starvation: most fish can forage, and if you have to go out of town, either have a sitter you can trust, an AUTOFEEDER, or don't feed. A pity-feeder who does not understand the danger can harm your tank. Also to watch---if you have cranky fish that might take after weaker ones, you need an autofeeder: Eheim makes a real good one, good for flake or pellet and will feed multiple times a day. a topoff accident: fish can stand a DROP in salinity. To raise it back to normal safely, just topoff with salt water instead of fresh. If you have a reef, there are other considerations, but corals usually just expell 'wrong' water and wait for conditions to improve. a few days without a skimmer/a week or so without a water change --- because---life, is all. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%. Last edited by Sk8r; 12/18/2016 at 04:29 PM.

12/18/2016, 10:18 PM	#2
CindyK Registered Member Join Date: May 2016 Posts: 268	We need a "like" button Thanks Sk8r! __________________ Taking "there is no such thing as a stupid question" to a whole new level. Current Tank Info: 75 gal mixed reef under construction, 32 gal Biocube softies

12/19/2016, 06:21 AM	#4
billdogg Registered Member Join Date: Apr 2008 Location: Grove City, Ohio Posts: 10,806	Nice list! If I could, I'd like to add to the bad list - Knee-jerk reactions to whatever you perceive to be happening. That will almost always lead to even worse problems. __________________ I'll try to be nice if you try to be smarter! I can't help that I grow older, but you can't make me grow up! Current Tank Info: 120 mixed reef with 40b sump, RO 150 skimmer, AI Sol Blue x 2, and a 60g Frag Tank with 100g rubbermaid sump. 2 x Kessil A360w lights, BM curve 5 skimmer

12/19/2016, 12:01 PM	#8
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	Only my koi like Cheerios---but they're in 5000 gallons of water. Nutrient overdose in a small tank can have really bad results real fast---as the tank tries to process, the oxygen-carrying capacity of the water goes down and down. The sad tale of the tank-sitter who says "well, they kept begging so I kept feeding" is why I say---train your tank-sitter and have your food pre-parceled for each day so there can be NO pity-feeding: even better set up dry food in an autofeeder. The reason the cure is a water change---dilution is the solution to pollution, where it comes to tanks. [It's a saying, not my invention.] The way you open a window to clear the air---clean water helps many situations. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%. Last edited by Sk8r; 12/19/2016 at 12:09 PM.

12/20/2016, 10:11 AM	#10
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	Experience, sadly. Caught in the act. Turned the lights on and the poor fish, though alive and waking, was in really sorry shape. Don't worry about nassarius---they're good snails. Just don't do a total blackout: it's not needed for cyanobacteria treatment: room lights only will do right fine. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

12/19/2016, 04:19 AM	#3
schnebbles Registered Member Join Date: Sep 2016 Posts: 475	Just what spike arm roommates are you referring to?

12/19/2016, 03:22 PM	#9
CrayolaViolence Registered Member Join Date: Nov 2015 Location: North Carolina Posts: 1,867	Do you have any links to documentation/studies about nassarius snails killing healthy fish? Thanks

12/21/2016, 10:45 PM	#11
Cancun Registered Member Join Date: Nov 2013 Location: Saint Louis Missouri Posts: 527	Great post Sk8r!!! And all so true! Yea...I also totally agree with billdog too....in my experience when you panic when something is out of whack....things get worse. __________________ Red Sea Reefer 750 XXL...I love wrasses....have leopards....several Coris....China Wrasse, Dejardini and purple tang... Current Tank Info: Red Sea Reefer 750 XXL

12/22/2016, 09:02 AM	#12
Elricsfate Registered Member Join Date: Oct 2016 Location: Fredericksburg, Va Posts: 482	Thanks Sk8r! I have a small Sally Lightfoot in my 75. I like the crab, seems interesting. But if it's a danger to other inhabitants I will leave it in the 75 when I move the other inhabitants to the 180. So that brings up the question, what are safe tank mates for these crabs? I'm not maintaining an entire tank for one crab. :-)

12/22/2016, 11:27 AM	#13
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	Sally lightfoots grow to about 10-12", and at that rate, eat what they can catch, particularly resting fish. I'd say trade her. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

12/22/2016, 12:22 PM	#14
Elricsfate Registered Member Join Date: Oct 2016 Location: Fredericksburg, Va Posts: 482	WOW! I have looked them up previously, and liveaquaria.com lists their max size as 3" That's why I was cool with getting one. Interestingly, if you Bing Sally Lightfoot you get these pics of a large, red crab. But the one in my tank is small, flat, and brown with stripes like the one that shows up if you search for Sally Lightfoot on LA's site. Are these two different crabs?

12/22/2016, 04:31 PM	#15
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	THey might be. I've seen travel videos of a place swarming with what they call sally lightfoots and it was scary. They may also be limited by tank food availability. But 3" across the shell is still pretty scary size for a tank crab that has fair-sized claws. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

12/22/2016, 06:16 PM	#16
Joe0813 Registered Member Join Date: Mar 2011 Location: Boston strong Posts: 2,766	I thought stray voltage couldn't kill fish? __________________ Joe and Jenny Current Tank Info: 180 reef

12/23/2016, 11:17 AM	#17
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	It's a complex question: yes, it's current that is harmful; but stray voltage can vary from mild to 'sends a shock to your elbow'. Any contact between electricity and water is not a good situation, which is one reason to be picky about brands of heaters---one of the common sources of problems. And of course, GFI's on all wall sockets used with water: that'll save your equipment, too. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

12/24/2016, 06:08 PM	#18
Joe0813 Registered Member Join Date: Mar 2011 Location: Boston strong Posts: 2,766	i had a few fish die a few months ago that were doing perfectly fine in my tank. then all of a sudden died. I did QT them. found a small GFO pump was zapping my tank... guess I found my answer to what killed my 250 dollar purple tang __________________ Joe and Jenny Current Tank Info: 180 reef

03/20/2018, 07:47 PM	#19
j.falk Registered Member Join Date: May 2017 Posts: 632	Nassarius snails can eat fish? I thought they mainly fed on things in the sand bed.

03/20/2018, 09:07 PM	#20
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	If your fish is sleeping on the sandbed they won't discriminate if the dark is total and the fish is deep asleep. This is why turning the lights out is safe, but blacking out the tank to pitch blackness is not. When we say 'lights-out' treatment for cyanobacteria, we mean keep the lights off, don't drape the tank. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

03/20/2018, 09:44 PM	#21
Bent I got nothin' Join Date: Nov 2004 Location: The anals Posts: 6,420	Mycobacterium marinum and Gram positive infections. Staph, strep and enterococcus. Gram positive infections have >50% mortality rate in fish. __________________ Quitters never lose. [QUOTE=CStrickland]Who gets mad at a starfish?[/QUOTE] Current Tank Info: 75g DT, 30G refugium, 10g chaeto tank, 50g stock tank basement sump

03/21/2018, 02:08 AM	#22
ramseynb Registered Member Join Date: Nov 2010 Location: New Braunfels, TX Posts: 630	Things that will and won't kill your fish So keeping alk levels at natural seawater levels is bad for fish? Hmmmm __________________ How do you make an octopus laugh? Ten tickles!