Backyard Aquaponics
A place to discuss aquaponics

I have a 55 gallon aquarium that I'm attempting to breed tilapia in. It has been set up about 2 weeks now. Have 2 tetra over flow type filters with carbon and soft filter media. There are a total of 8 fish, from 3-6 inch. My ammonia spiked last after 3-4 days, and now has dropped down to almost zero. Nitrites are through the roof- 2- 5 ppm, honestly can't tell between the 2 shades. Fish were flashing a few days ago, so did 50% water change. rechecked Nitrites right after change, still 2-5ppm. Then same yesterday, and level still 2-5ppm. I have cut back feed from 3 times per day to 1 small feeding. At this rate, my breeding success is not looking promising. I'll clarify, my fish breeding attempt. The wife and I have three lovely kids.lol

'carbon and soft filter media' - I don't know about filters - what in there would be a biofilter? It sounds to me like you thought the filtering would remove everything but the description sounds like you are trying to do AP without the plants. If so, it has to cycle before the nitrites will drop.

I'm guessing but I think your soft media (what is it?) is forming a bio-filter so you have bacteria creating nitrites but not yet making nitrates.

You might need to get someone with aquarium experience to help.

From my small system same thing happened and I cleaned the beds as best I could and changed the water but did resort to a chemical biofilter to add to water over 7 days and it has helped. I also introduced a bamboo plant which helps filter and I just learned about that. Fish are doing fine even though the nitrate level could use lowering still working and it has been over 3 weeks so I think you need to give it some time and make sure you have plenty of oxygen and see it you can get some plants floating in tank like duckweed to help with filtration. I got some red wrigglers and introduced them and they are definitely helping as well.

I had the same experience with high nitrites that you did. I finally got them down in week six. I did 15 gallon water changes three or four times a week starting in week 2 and could not get the level down. Starting at week five, I did 15 gallon water changes every day for about 7 days and finally the nitrite level dropped to zero. Not sure if it was the daily water changes that gave the bacteria a chance to get it under control or if it just took a full six weeks for the bacteria to develop and start working. I have a 50 gallon aquarium with seven 3-4" blue tilapia. I have the 60 gallon Tetra filter with charcoal and mesh looking black media that came with it.

Mike, just this past weekend they finally dropped. resumed feeding and am seeing signs of breeding activity. We'll see if they hold steady and if I see any fry in the next few weeks. Thanks for all the replies...just a matter of being patient. This is definitely NOT a hobby I would have enjoyed in my younger years.lol I'm infinitely more patient then I was before kids, and now am able to better tolerate all the "waiting" that seems so common in this AP world.

My levels have been down for two weeks. I have one male that has established a territory, but has been unable to convince any females to join him.

The males are usually wanting to mate if the water is warm enough for them to want to eat. The Females seem to need warmer water to get into the mood (at least in my experience, I didn't see much breeding going on until the water temps got up in the mid 80's F.)

I actually had a few females killed by aggressive males when the water was down in the mid 70's and the males just wouldn't quit chasing the females. Of course I didn't have a big enough breeding tank so there were only a few females for the male to chase and that stressed them out way too much. I also had far better luck with 300 gallons of tank and about a dozen fish and when the water got up into the mid 80's F I had way more fry than I knew what do do with. (by the way chickens love pumpkin seed size tilapia, a moving bite size snack that is easy to see flop around and can't get away!)

I'm not actually bothering to grow tilapia anymore because I'm unwilling to heat the water and my best crops also like cooler water so my primary fish is catfish now.

My temp is set to 82 degrees. I will raise it up over the couple days to 85 and see if that helps any.