Problem with zebra danios
 

My zebra danios used to swim together nonstop but now they are still swimming nonstop but they are staying on oppisite sides of the tank and wont get near eachother. What happened and what can i do to fix it?

Danios are shoaling fish, that is, they live in groups. When kept as only two, such fish sometimes develop different behaviours, aggression, etc. If you like the zebra danios and want to keep them, I would suggest adding a few more to create a small group (shoal) which would make them feel more comfortable. I realize you only have a 10g tank, but if you are regular in your weekly partial water change and don't overfeed, 3 more zebra danios will be OK. But that would be the limit in this tank. Danios are active swimmers, and a larger tank is worth considering.

Byron.

Yeah i am planning on getting a 30 gallon. I went to buy more zebra danios yesterday but i also had my water tested and my ammonia was at 3 mg/L. I found out that the cause was that my tap water had high ammonia so now i let my water age 48 hours before putting it in the tank. I am going to buy more zebra danios once i get the ammonia under control. Also the ammonia doesnt seem to be affecting my fish cause they are all swimming happily. i already have my ammonia at 0.07 mg/L. I normaly do every 4 days a 20% water change but i have been doing daily 25% water changes to get the ammonia down.

Ammonia should never be present in an established aquarium; it is very stressful at low levels and highly toxic if it should rise. Once a tank is cycled, ammonia should always be zero when tested, always. The daily partial water change is what is keeping your fish alive; the presence of any ammonia probably explains the sudden behaviour change of your danios. Ammonia in your tap water can be dealt with by using a good water conditioner like Prime; it not only detoxifies chlorine and chloramine but also ammonia. Letting water sit 48 hours will not remove ammonia (or chloramine). And chloramine and ammonia are related. Use Prime as your conditioner and you'll be fine.

Byron.

Next time i go to the LFS I will look for prime and if i see it i will buy it.