Whats wrong with my malawi cichlids?

Question

This morning I got up to find all my malawi's on the surface of the water, looking like they are gasping for breath!! I quickly took the filter out and gave it a good clean as i found it was filthy but i only cleaned it 3 weeks ago, its a fairly new fluval 4, in a 180litre tank. In the mean time I put an air pump in the tank to put some oxygen in the tank whilst i cleaned the filter, After I cleaned the filter and put it back in the tank, all the fish started to behave normally, but im still worried as they didnt eat their food!! I only did a 20% water change yesterday and tested the water and all was fine. Do you think that it was just the filter?

My tank has been cycled for 3 months now, the water test kit is 3 months old and i tested:-
Ammonia - o
PH - 7.5/8
Nitrat - between 20-50
Nitrit - 0.1
This is why i am confused!!

Answer 1

What were the results of your testing (and what parametrs were tested)? Too much ammonia and nitrite mimic too little oxygen, and will cause fish to gasp at the surface.


ADDITION: The nitrite level is a little high - this should be at 0 if your tank is cycled. It may have been even higher before the water change, plus would have needed an ammonia spike previously to form the nitrite. The nitrate may be as high as well, since some fish start to show a reaction around 40ppm. I'd say another partial water change is needed, and to use a siphon to clean the gravel if you don't use one regularly, and up the volume of your regular water changes to 25% each week. I'm assuming that since you've got Africans, you keep salt in their water - this probably kept them from more severe nitrite poisoning.

Cleaning the filter would have caused the loss of some beneficial bacteria, but most of these should reside in the substrate.

http://freshaquarium.about.com/cs/disease/p/ammoniapoison.htm
http://freshaquarium.about.com/cs/disease/p/nitritepoison.htm

Answer 2

Gasping at the surface is a sign of ammonia poisoning.I don't know much about this type of filter but cleaning it out the filter is probably the worst thing to do during an ammonia spike as you will disrupt the beneficial bacteria.

I would do a water change again and take your water in to a fish store to be tested,most of them will do that for you and its possible your test kit has gone bad.Also if you are using test stripes instead of a liquid kit they are some times not as accurate.


How long has your tank been set up,if it a new tank it may not be fully cycled yet.Make sure you don't over feed or overstock your tank.

Answer 3

What was the temperature of the water,if the temp is to high it will certainly gasp. The temp should be the same as a warm living room 78f.