Dr. Roy Caldwell Q & A #2: Glass or acrylic?

moviegeek · 03/19/2001, 10:13 PM

Dr. Caldwell,

In your lab to you keep your animals in glass or acrylic tanks? I've received several e-mails from people asking me if an acrylic tank is "necessary" for a 6" size smasher. I have been recommending acrylic, although some people are using glass with no problems reported. Do you keep heaters in the tanks with the mantis, or are the heaters in a sump or overflow compartment? I have been telling people not to put heaters in with the shrimp, after witnessing my mantis accidentally breaking a thermometer in two while chasing a goldfish. It seems reasonable that even a 3-4" smasher would be capable of breaking the thin glass of a heater.

Thanks,

Adam Jones

We use both glass and acrylic tanks. Usually there is no problem with even a large O. scyllarus, but I have had them break glass tanks. This usually happens when an animal tries to dig and runs into the corner and tries to chip away what it sees as an obstruction. Eventually they will chip the glass and cause a leak. This is rare and it takes a large animal to do it, but I can think of at least 4 times that it has happened to me (but then I have been keeping stomatopods for 30 years and usually have dozens in the lab at any one time). The most dramatic failure I have ever had was in one of my photographic tanks made from single thickness window glass. An 8 cm Gonodactylus chiragra (pound for pound, the strongest striking stomatopod that I know) got into a fight with its reflection. It coiled, then landed a solid double strike to the middle of the glass wall taking it out in spectacular fashion. Fortunately, I was using a a fairly long macro lens and the camera was far enough from the glass to only get a few drops of sea water on the lens.

Heaters are a different game. I have lost dozens of heater (and stomatopods) over the years to heaters. We used to use racks of 10-20 gallon tanks with only canister filtration. Each tank had a heater. There were two situations that caused the stomatopods to strike and break them. The first was the orange "on" lights. The animals would see the light blink on and strike at the sudden change. The second I think was caused by the heater being hot. The animal would make antennular contact which caused pain and it would strike. Of course once the heater broke, there were problems not only with electrocution, but with toxic heavy metals being released into the tank, so we would have to start from scratch. We used to place 1 1/2 inch thin plastic tubes (with holes cut into it) around the heaters to keep the stomatopods from contacting them. Still, they often slipped and we had the occasional disaster. All of our larger tanks has sumps, so the heaters were placed out of contact with the stomatopods. About 5 years ago we moved into a new laboratory with separate aquarium facilities. The room is kept at 27 C, so we no longer have to use heaters. Now our only problem is evaporation.

As for thermometers, it seems that every student in my lab has to learn the hard way. They invariably try chasing an animal around the tank with the thermometer or hydometer and the animal breaks it. Fortunately in this digital age, we now use mostly thermistor leads and thermometer breakage is no longer a problem.

Roy

***************************************
Roy L. Caldwell
Chancellor's Professor
Department of Integrative Biology
University of California at Berkeley
Berkeley, CA 94720-3140
USA

03/19/2001, 10:13 PM	#1
moviegeek Premium Member Join Date: Nov 1999 Location: Chico, CA (Nor Cal) Posts: 826	Dr. Caldwell, In your lab to you keep your animals in glass or acrylic tanks? I've received several e-mails from people asking me if an acrylic tank is "necessary" for a 6" size smasher. I have been recommending acrylic, although some people are using glass with no problems reported. Do you keep heaters in the tanks with the mantis, or are the heaters in a sump or overflow compartment? I have been telling people not to put heaters in with the shrimp, after witnessing my mantis accidentally breaking a thermometer in two while chasing a goldfish. It seems reasonable that even a 3-4" smasher would be capable of breaking the thin glass of a heater. Thanks, Adam Jones We use both glass and acrylic tanks. Usually there is no problem with even a large O. scyllarus, but I have had them break glass tanks. This usually happens when an animal tries to dig and runs into the corner and tries to chip away what it sees as an obstruction. Eventually they will chip the glass and cause a leak. This is rare and it takes a large animal to do it, but I can think of at least 4 times that it has happened to me (but then I have been keeping stomatopods for 30 years and usually have dozens in the lab at any one time). The most dramatic failure I have ever had was in one of my photographic tanks made from single thickness window glass. An 8 cm Gonodactylus chiragra (pound for pound, the strongest striking stomatopod that I know) got into a fight with its reflection. It coiled, then landed a solid double strike to the middle of the glass wall taking it out in spectacular fashion. Fortunately, I was using a a fairly long macro lens and the camera was far enough from the glass to only get a few drops of sea water on the lens. Heaters are a different game. I have lost dozens of heater (and stomatopods) over the years to heaters. We used to use racks of 10-20 gallon tanks with only canister filtration. Each tank had a heater. There were two situations that caused the stomatopods to strike and break them. The first was the orange "on" lights. The animals would see the light blink on and strike at the sudden change. The second I think was caused by the heater being hot. The animal would make antennular contact which caused pain and it would strike. Of course once the heater broke, there were problems not only with electrocution, but with toxic heavy metals being released into the tank, so we would have to start from scratch. We used to place 1 1/2 inch thin plastic tubes (with holes cut into it) around the heaters to keep the stomatopods from contacting them. Still, they often slipped and we had the occasional disaster. All of our larger tanks has sumps, so the heaters were placed out of contact with the stomatopods. About 5 years ago we moved into a new laboratory with separate aquarium facilities. The room is kept at 27 C, so we no longer have to use heaters. Now our only problem is evaporation. As for thermometers, it seems that every student in my lab has to learn the hard way. They invariably try chasing an animal around the tank with the thermometer or hydometer and the animal breaks it. Fortunately in this digital age, we now use mostly thermistor leads and thermometer breakage is no longer a problem. Roy *************************************** Roy L. Caldwell Chancellor's Professor Department of Integrative Biology University of California at Berkeley Berkeley, CA 94720-3140 USA