Strange creature growing in my tank...

[isisshai]

I have a tank with frogs and fish. I have discovered a creepy creature living underneath the gravel filter. I managed to capture two of them, they are 2 times the size of a grain of rice, and clearish, pinkish, greyish and worste of all they have legs. Can someone tell me what they are and how to get rid of them? I have very warm water that I keep clean, not sure how they grew in my beloved aquarium. Thanks

[Fruitbat]

isisshai...

Welcome to Aquarium Advice!

It is very difficult to identify your 'strange creature' without a picture but I'd suspect you have one of two things: 1) Gammarus or one of its relatives...these are small freshwater shrimp-like creatures or 2) some sort of insect larva. In either case these things are most likely harmless to your fish and, since they're living beneath your UG filter, they will be very difficult to exterminate without tearing your whole tank down. Any chance you could post a picture??

[TankGirl]

Here is my reply from your duplicate post, which I deleted:

I am not sure - any chance you could take a pic of them?

When you say legs, do you mean half a dozen legs like a bug would have, or many legs that would be hard to count? Do they have a recognizable "head" or are they uniformly oval shaped?

There are several ways they could have found their way into your tank. Live plants could have transported them, and even in their larval form in the gut of a new fish or frog, or if you feed or have fed live food it could have happened then.

Many, maybe even most uninvited [acronym:df891c262d="Freshwater"]FW[/acronym:df891c262d] aquarium guests are not harmful, but no matter what they may be the key is going to be to starve them. Your fish and frogs can go for a week no problem, even ten days, without eating, so I would either cut back drastically on feeding or stop altogether for a period of time. Take an airline tube and make a syphon and feed it into your [acronym:df891c262d="Under Gravel Filter"]UGF[/acronym:df891c262d], and try to suck out as much debris as you can so there is nothing for them to live on under there. You could turn your [acronym:df891c262d="Under Gravel Filter"]UGF[/acronym:df891c262d] into a reverse-flow system with a powerhead, so the water flows up from underneath towards the water column instead of being drawn down under the gravel, and there might be less of a chance for them to survive like that.

Another thing to do is to simply raise the temperature of the tank up to about 86F, provided the frogs can handle that (I've not kept frogs so not sure about it). Some creatures like this can't tolerate high temps.

Good luck!