Quarantine tank killing fish! Help!

[ekane]

I just put some fish in a QT tank and all of them died overnight! I need help figuring out what went wrong! Here's their (very detailed) story:

I am new to SW tanks, so thought I would start off with a light load (i.e. not corals). I recently adopted some wild-caught Trinidadian guppies and sailfin mollies from a research lab that couldn't use them anymore (just used for breeding, no chemicals etc.) and acclimated them up to full salinity (1.024) over about a week in a 2g bucket sitting in my DT to match temp. Both sets of fish were housed in bare tanks (i.e. quarantine) for at least 2 months, the mollies about a year, before I received them. I didn't have any deaths during the week acclimation so I put them in my DT (cycled with live rock/sand for about a month before adding fish) as soon as the salinity was matched. All fish seemed to be happy and healthy - the female mollies were doing their vertical bobs to attract males and I found several guppy babies. Then black friday hit and the LFS had a big sale, so I was talked into a cherub and a rusty angelfish. I floated both (separate bags) and added to my DT that night. Perhaps this was my problem since they weren't QT, but the LFS said they were in the store for about 3 weeks, one in a bare tank.

The problems started a few days ago when I saw that most of the guppies were covered in white spots. I have seen FW Ich before, and this looked similar. I scoured the internet for treatment of SW Ich, and read that I should separate the fish from the rest of the tank so that the external parasites on the fish will die and not be able to complete their life cycle, and the ones in the tank will die without a fish host. In an effort to remove the fish immediately and get the parasite-killing started, I set up two tanks (one for guppies, one for mollies, and split the angels one in each tank) with water from the DT, a small heater, a new-in-box HOB filter, and in an effort to seed the filter, a foam insert from the DT canister filter. I propped up the canister foam so that the outflow from the HOB would flow through it. Since the QT tanks had water the fish were already acclimated to, I put the fish straight in (again, start the parasite-killing). I did not feed that night. That was about 24 hr. ago.

I woke up this morning and both angels and about 5-8 guppies were dead. I scooped all dead fish out and tested the water. My strips only test nitrite/nitrate, pH, and alkalinity and all were "normal" according to their SW chart. Temperature was spot on 78, matching the DT they came from. I came home from work this evening and all remaining guppies and 1 molly were dead. The remaining mollies look terrible: clamped whitish fins, thin, swimming funny. Naturally, I was a bit freaked out by this, so I immediately tested the water again, same result, and not trusting my test strips, took some water to the LFS to test. They thought it might be ammonia but that tested <0.25 and he said that shouldn't kill fish overnight. But he insisted the only thing he could think was not enough cycling of the QT tanks. I probably shouldn't have, but in an effort to save the remaining mollies I just put them back into the DT.

Any ideas of what is happening in my quarantine tanks? Was the new filter an issue? I realize now that I didn't rinse it before I used it, but I haven't had this trouble with filters in the past. I need to figure it out so that if I get new fish and QT them I know the tanks/filters are ok. This is killing me that I can't figure it out! Thanks for any help!

[droog]

How big was the tank, how much rock/sand and how long has it been running (was it fully cycled)?

Originally Posted by ekane

...and in an effort to seed the filter, a foam insert from the DT canister filter. I propped up the canister foam so that the outflow from the HOB would flow through it.

I think that could be part of the problem also, the foam insert may have had trophonts / tomonts on it.

It may be the fish were too stressed from the initial parasite infestation to survive whatever you did. You still need to treat once they are in a QT... copper, CP or tank tranfser method.

Buying fish on impulse is risky. You (and your livestock) paid the price this time, but use it as a learning exercise and don't lose heart. Sounds like you tried your best to recover the situation, just not to be this time.

Read the stickies on this site. Canister filters are not so common with SW as they are with FW as they tend to produce a lot of nitrates.

Good luck!

-droog

[ekane]

Hi droog,
The DT is 65g with 4" sand bed and about 30lb live rock. It has been running for about 2 mo and yes it is fully cycled.

Thank you for your suggestions. There could have been some parasites on the foam inserts, but I actually didn't see any of the white spots on the dead fish I pulled out, so I don't know if they "jumped off" when I put the fish in the QT tanks? The fish did not appear stressed in my DT and were eating well. I don't think the stress occurred until I put them in the QT tanks, but given that they were in similar setups just prior to being in my tank and were fine, I don't think the bare tank in general was too stressful for them. It makes me think there is something else in the water or filter that lead to the deaths.

I guess you're right that the angels were relatively impulse buys, but I had been thinking about something else to get for a while and had been looking into lots of options, just settled on the angels at the time. Also, I already had the canister so thought I would go with that. I did a lot of research on filtration methods, and I thought about setting up a refugium, but the way my stand is built it's difficult to get another tank in/out and would be difficult to access the tank once it was in there. I haven't had problems with nitrates so far, and from what I've read a small dose of them is actually good for the macros.

**Update** this morning in the DT 3 more mollies were dead. The remaining mollies look like their fins are rotting/shredded, and they all look like they are wasting. Some are swimming at about a +30deg angle. Is there something that causes these symptoms? If so, perhaps that's what is in my QT tanks? Heavy metals? Some other toxin?

[Sk8r]

Probably the culprit was lack of oxygen.
The angels brought in ich, quite likely. If one tank at the lfs has ich, probably they all do: most stores have shared water systems.
Two mini-angels in a 65 is too many.
Ich doesn't fall off. The white spots are pimples that burst and emit swimmers which lodge in filters and sandbed, to grow and reinfest a fish. This is why I use plain white floss, no cycling, in a qt tank, floss changed daily. No dirt = no cycle = no ammonia.
The mollies have now complicated their situation with a bacterial infection.
Saltwater adaptation of mollies is dicey, and really not the best thing for a marine tank.
You probably need a much stronger pump for your qt, and you should not have more than one fish in a qt at a time, except for a mated pair.
Reefs (corals with fish) don't use filters and generally (if well set up) don't have issues with nitrate and ammonia because the live rock and sand dispose of all waste. Fish-only tanks may use filters, but you have to keep a close watch on nitrate/ammonia: any ammonia at all is not a good thing.
Up in the stickies atop this forum is a 'book' titled SETTING UP. Give that a read.

As I understand it your dt has now been infested with ich. Do not get another fish for 12 weeks...time enough for the parasites to starve to death. You can have one in qt at 8 weeks, but keep him under observation for 4 weeks before putting him into the dt.

You can safely get invertebrates like snails and mini-hermits to go in the dt to give you something to watch. They don't get ich. Any fish in there will simply lengthen the waiting time.

[ekane]

Hi Sk8r,
Thanks for your comments. The HOB filters had strong flow in the QT tanks, but I guess there still could have been low oxygen. Noted RE: the mini angels. Next time (>12 weeks) only 1.

So is there no hope for the mollies at this point? What should/can I do for them? There are only 6 left. When the mollies were collected they were in high brackish water around 28ppt so I thought they would be fine in a marine tank. They are wild-type, so probably better at handling salinity that tank-bred specialty versions.

[Sk8r]

I think what you need is a brackish tank. I maintained one for scats and metynnis for years---the scats grew saucer-sized and are very personable.

But first you need to get those poor mollies to survive. If they have no ich, you might treat them in a bare qt with something like Maracyn, and just keep changing filter floss daily. The catch is, the fin-rot is bacterial and must be treated with an antibiotic. What broke out in spots is ich, a parasite, which is often treated with copper, which cannot be combined with antibiotics. Another method of treating ich, however, is what we call tank transfer, meaning new tank every day, like changing a goldfish bowl---when the little swimmers leave the pimples, they get swept away instead of finding a home in sandbed or filter. But changing the floss daily for fresh (I use artifiical pillow stuffing from fabric store: cheaper!) will serve the same (though not quite as efficient) purpose as tank transfer. And you CAN do that while dosing antibiotic.. I applaud your concern for the mollies. Hope you can save them!

[ekane]

Thanks for the great advice! The guy at the LFS told me to just leave the tanks set up, but I will try your bare tank method. I'll completely change all the water and pick up some floss and Maracyn tonight on my way home. I can also add an airstone to the QT tanks just to be sure there's O2. There's a long story behind the mollies, but in essence, it took a lot for me to get them to my tank, so I want to make sure I can keep them there!

[Sk8r]

YOu can use white vinegar to wash out a tank: won't hurt. BUT do be careful to sterilize the nets and other such so as not to carry ich from the dt to the qt: real hot water should work, then just rinse in a little salt water. This is why I use my hands to move fish. Sometimes I also give them an intermediate dip in new saltwater on their way to another tank, so that anything swimming with them stands a good chance of getting left behind. Treat it as a contagion: ich swimmers are too small to see without a microscope.

[ekane]

Hi Sk8r,
Yes I know the vinegar trick and I was planning on doing that but didn't mention it. I always do that when I break down a tank (or buy a new one). I never use my hands because I was taught that the oils, etc. on your hands can be bad for the fish, particularly those without scales.

[Sk8r]

I do use my hands (but sparingly!) because nets can catch and wound. Many marine fish have a barb on their operculum (gill cover) and if this gets ripped, it's bad. i use a combo of hand, little bucket, and sometimes a net if I'm trying to catch a misbehaving fish---but in general if you use those exam gloves you get from the pharmacy (and rubberband your wrist if you have a sore on your hand you don't exposed to harbor water from Singapore) you can use your hand safely on corals and still have good tactile sensation for what you're dealing with.

[ekane]

**update** All fish have died. This actually happened yesterday morning but I haven't had time to post an update yet. I guess now in 12 weeks I can try again. Thanks for everyone's help!