Crud in My Tank... Algae?

[RedAngellion]

Hello, all. This is my first post here but I've browsed before when I've had questions. Well, I have one now and couldn't find a thread with the answer.

I have a 55 gallon tank with a single occupant, my ~7 month old male Axolotl. For substrate I use pebbles which I bought at a nearby pet store. I have a few (non-living) aquarium decor plants and a little castle.

Anyway, over time the tank has also become home to... I'm not sure what to call it, exactly, but I'll try describe it as best I can; it's brownish-clearish algae-like stuff. It sits at the bottom in the substrate and clings to the plants and the little castle, and also gathers somewhat on the glass. When disturbed, it floats about and eventually settles again. I suppose you could say it looks like little bits of torn up tissue.

I do 20% water changes every week, and I have two sponge filters. I use a syphon to do the water changes and I try to suck up as much of the crud as I can along with waste. For the first few months, I was feeding frozen blood worms, and he's now on ReptoMin pellets. The tank gets very little sun, pretty much none at all. I have a water test kit and I test regularly for Ph, Nitrates, Nitrites, and Ammonia; all numbers have been great.

I've looked through Google Image results for a couple different types of Algae but found nothing that really looks like the stuff in my tank. Does anyone have any idea what it is?

[Jennewt]

I don't know what the stuff actually *is*, but I have a couple of suggestions. First, keep up with what you are already doing and remove as much as you can by siphoning. Second, consider getting some live plants, if there's enough light for them. Third, consider getting rid of the pebbles. There are two problems with the pebbles. They can be swallowed. If you don't think so, look at the xray on this page
Caudata Culture Species Entry - Ambystoma mexicanum - Axolotl
I have a similar xray from someone else, so this is not a fluke occurrence. Axolotls will gulp down anything they can, even if you never see them do it. The other reason for ditching the pebbles is that they can hide uneaten food. Even if it's not enough to send your water parameters out of whack, it may be enough to nourish this crud, whatever it is. What kind of food are you using?

[RedAngellion]

Yes, I was aware of the swallowing issue. The pebbles are pretty big. When I first got my axolotl, they were much, much too big for him to even think about getting in his mouth. He's grown quite a bit at this point but they're still, for the most part, too big for him to fit in his mouth, but that won't be the case forever, so...

I DO need a substrate of some kind, don't I? If so, what kind would you recommend replacing the pebbles with and do I need to do anything special before removing the pebbles?

Like I said, I started out feeding him frozen bloodworms, but I switched to ReptoMin pellets about two months ago or so. The pellets float and I feed him by hand so there's very little, if any, uneaten food that ends up in the tank.

What live plants would you suggest? One end of the tank is near a window. I usually keep the window covered because I read that axolotls don't care for a lot of sunlight, but I could open it to let some sunlight in for the plants.

[Jacquie]

Bare bottom tank is safest. However, if you prefer a more "natural" look, and prefer substrate to help anchor plants, sand (freshwater aquarium sand, or children's play sand, or pool filter sand) is the next best thing. When the axolotl swallows the sand, he will be able to pass it with ease.

Java moss and java fern do well in dim conditions. Axolotls don't care for light as they have no eyelids, but if you provide some hides so the axolotl can get away from the sunlight if it is bothering him, keeping the window open to give the plants light should be fine.

[RedAngellion]

Thanks a ton. I was under the impression that a substrate of some kind was necessary. Bare-bottom would sure be easier to keep clean. I suppose I'll try that.