New Filter. Oxygen Problems? Dying Livestock

[Valentini]

I just checked it. There are some particles, but not enough to account for the level of cloudiness. If this were bacteria, would it be harmful to my fish? They're still gasping and my puffer swims weakly. I'm very worried about the puffer. I love her

I got the old filter to work again, which restored the circulation levels to what they were when the fish were healthy. I also have an airline with no stone
in the corner for good measure. I had a bag of carbon in it for a couple of hours, but I can't fit it in this filter so I took it out. The fish seemed to perk up when I had it in there. Ammonia and stuff is still at 0.

 

[Donya]

The bag of carbon can just sit in the tank if it's tied a the top; it doesn't have to be in a filter, it's just most effective when in flow. Just wedge it near the output if possible and leave it in for a few days. Or, if you have the canister hooked up still, you can also take some ceramic rings out and stick a bag of carbon in their place if there's no space.
 
If it's a bacterial bloom, there it not a lot that can be done except to wait it out and do daily water changes as a precaution against spikes in any params. Usually bacterial blooms of the cloudy water sort aren't harmful, just a symptom of biofilter instability and an eyesore. The bacteria are just the same ones that are in the tank normally, so it's mainly ammonia/nitrite/etc. spikes and pH dipping during the period of instability that are the bigger issue to watch out for. 

 

[Valentini]

I did place carbon in the filter overnight. When I woke up and turned on the lights, the water was much clearer and all the fish greeted me like usual, including the puffer. I fed them, and everyone ate except the puffer. When I got home from school, everyone and the puffer ate and there is no more gasping. All parameters are good. I'm very happy, but still sad that I lost the angel

 

[Donya]

Glad to hear things are settling out. Sudden, unexpected things like this happen to everybody at some point or another; it's one of the unfortunate hazards of the hobby. You handled it well! 

 

[xXLeafeonXx]

You do know, that you have a puffer and two firefish in that tank right? From what I know puffers are aggressive. I hope your firefish are okay. Although I'm not sure if that puffer is aggressive or not. You do seem to have abit of fish I hope you have a good protein skimmer.