Hiya everyone. I have a fairly new tank and have some swordtails as well as a couple of mollies in it. I am worried about one of the mollies. He is just sitting on the gravle at the bottom of the tank and I dont know if thats normal for a mollie but I dont think it is. He will swim up when I feed them, but then just sits on the gravel again. he is moving all his fins and everything. Is something wrong?

Hiya webby. Can you give us a few more bits of information so we can help? What size tank have you got and when was it set up? How did you set it up - did you do the fishless cycle or just add fish? How long have you had the fish?

Sorry for all the questions but it will give us a better idea what is going on.

Hiya Diana, ok, It is a 90 litre tank, not sure what make but its got an in lid filter and lights. It was set up about 4 weeks ago. I added water and some stuff from the pet shop that builds up the filter. Ive had the fish for three weeks.

Does that help?

Have you got a water tesing Kit webby? to test for Ammonia Nitrites Nitrates etc

Hiya GD, sorry I didnt reply last night. I havent got a testing kit, but could get one this morning. Is that what I need do you think. What type of kit should I look for, or are they all the same?

Hiya webby, you do need a decent water testing kit - the API Masterkit is generally thought to be the most accurate. If you havent got that then until you get it I would do daily 50% water changes (dont forget to add dechlorinator to every water change) just to make sure that water quality stays reasonably good.

There is a chance that your tank is being cycled with fish. Have a read of the information on Cycling with Fish written by Mary, you will find in in the Aquarium Articles section of the forum.

Hi Webby. Well it sounds like the tank is still going through its cycling process (i.e. establishing the filter bacteria) which can have an adverse effect on the fish. Post the test results for ammonia, nitrite and nitrate asap and that'll give a better indication.

Thanks everyone. From what I have read now I need to test the water every day, and then it's just changing the water to get the ammonia and nitrite and nitrate down is that right? Also, how often would I need to wash the filter foamy bits?

I wash the foam about every three weeks or so in some of the water taken from the tank. NEVER wash it in ordinary tapwater because it kills off some of the bacteria.

Nitrate is the good bacteria

Ammonia and Nitrite are EVIL

Nitrate's a bit bad too, just not quite as much, hence the need for water changes to keep it under control.