Backyard Aquaponics
A place to discuss aquaponics

I have six medium sized tilapia in a tank with goldfish and some rosy reds. Yesterday, I found two partially eaten goldfish floating in the tank and noticed that I'm not seeing as many of the rosies.

I thought that tilapia were herbivores. There is nothing else in the tank that would eat the goldfish. Am I feeding them too little? Are they looking or more protein? They are growing very quickly and I feed them several times a day.

Tilapia are opportunistic and omnivorous. I do experience predation from time to time, especially if the tankmates are smaller. They do need higher protein as young fish, and shift to more veggies as they get older. For grow-out, a 30% protein feed should be fine. For young fingerlings, I think I use 45% protein. I would just say you've chosen the wrong tankmates. Can you move the smaller fish out?

Info on Tilapia in General
http://www.thefishsite.com/articles/58/ ... nd-biology

This is the feed I use for growout. 35% protein
http://www.zeiglerfeed.com/product_lite ... Bronze.pdf

A+ on that one Janet. My largest fish had half her tail missing this morning. I have moved the smallest and untouched fish to a seperate tank and isolated all the others from one another.

RP it sounds like you have the same problem....This is going to be a pain to keep seperate tanks.... Oh well, I guess it's time to get started on it...

I'm actually OK with the tilapia eating the goldfish, they were food for my son's turtle in any case. If they bring some added protein to the tilapia, I guess that's just nature's way.

It is surprising though, based upon what I've read.

The cichlid fish aggressity is manageable as long as the densities of fish are to important to let them have a territory. High density (crowding) is the key to good tilapia farming.
Jazz it could have been possible that the small one didn't have any territory to defend and then was out of the fights so didn't get hurt.
Tilapia eat everything from microscopic algae to fish that is why it is the third cultivated fish specie in the world, volume wise.

My tilapia kill goldfish close to their size but leave smaller feeder goldfish alone. I'm guessing the tilapia are protecting territory and they find the larger goldfish threatening. Perhaps they are jealous of the coloration? :0

Well there is a lot of chasing going on in a goldfish pond that I recently introduced some Tilapia fingerlings into. Maybe I should go and have a look how many goldfish I have left.

I know this is old, but...

I started my 50 gallon system last winter, cycled it with 30 rosy reds for several months, then added a large gold fish from the spring fair which grew to about the size of a silver dollar (2"-3"), pretty big. I added 12 tiny tilapia about 2 months ago. They have grown very fast.

Over the last three weeks I noticed the rosy reds are slowly disappearing and yesterday I realized my large goldfish has disappeared. Not a trace! I hadn't payed much attention the last few days when feeding. I have some large head of water cabbage from the local spring fed lake in the tank so seeing deep into the tank isn't easy without moving it aside (the tilapia love to eat the cabbage). So the goldfish could have been gone for a few days without noticing.

I only lost a three rosy reds in the first month and haven't had a fish die since, so I'm pretty sure the tilapia are eating them.

It doesn't surprise me about the rosy reds getting eaten, but a huge goldfish almost the size of the tilapia?

It is getting a bit crowded and my plan is to add a 250 gallon tank soon, but I was surprised to see so many fish gone so quick. Do you think there's not enough room?

50 gallons, 12 tilapia about 3", and about 15 rosy reds.

My water tests show the ammonia and nitrites are staying at zero over the last two months and while I had the Nitrates staying between zero and 5ppm it has spiked this week to about 20ppm.

I'm adding more plants this week to try and lower the nitrates.

Do you think I'm over crowded or maybe some particles of dead fish floating around from the goldfish feast?