Angelfish Laying On Bottom of Tank

Question
Hi there,

I just got a new freshwater aquarium setup, it was used and came with several fish. The fish thats sick is the approx. 4 inch long angelfish that is the centerpiece of the aquarium. When I first reset the tank up, the 2 angels both wouldn't eat, and were kind of hanging out near the bottom. After I became aware of the huge amount of anaerobic bacteria in the bottom, which reeked of rotten eggs, I completely took apart the tank and put in new gravel for the bottom. Since then, my smaller angel seems to have recovered and is eating fine. However, my larger angel has gotten worse. Last night he was doing random flips, and this morning, he was laying on his side. I tried to feed him peas, but could only get about 1 pea, in 6 bites for him to swallow. Please help me, should I keep trying to let him recover, or should I euthanize him. Thanks for the help,

Justin

Answer
Hi Justin,
Yikes! Anerobic conditions in the aquarium to the point of a rotten egg smell is never good!

Your angelfish are going to be stressed out from the previous anerobic conditions, the complete change over of new water, and the fact that your aquarium likely now is going to start re-cycling. Or re-establishing the biofilter --- the good bacteria that keep ammonia at bay. The majority of these bacteria live in the gravel bed so switching over to new gravel means losing a good portion of the biofilter.

So you must be careful of the possibility that ammonia may start building up unchecked. You can test for ammonia or bring a water sample to your petstore. Partial water changes are your best bet for keeping ammonia under control until the good bacteria can re-establish which can take a couple of weeks.

I would give the angelfish some more time. I might go ahead and do a 30% water change just in case ammonia may be building up and stressing him. Just make sure to use water conditioner with all new water and ensure the temp is as close to your tank's temp as possible.

The sickly angel may just be too stressed. They are very expressive fish when they aren't feeling good or conditions are not very favorable.

I do hope he recovers. At least you are trying your best to help him!

Good luck!
Susan~