my two giant firemouths are killing all the other FMs

[rosiesfishpond]

help! i’ve had a (heated) cichlid pond here in south florida and my two largest Firemouths which are gorgeous, are literally killing every other firemouth in the pond. this just started two weeks ago. I’ve always added different cichlids that are compatible so they aren’t upset about newbies. The only other change is that i’ve had a few unexpected pregnancies, so there are many more fish than before. it’s a 1000g pond so there’s (or was) plenty of room. I’m planning on rehoming the babies (teens now) to the lake out back. It’s getting overstocked. Since the babies arrived, the nitrates went from 0 (used to have better readings than my indoor tank which is around 10 nitrates) to around 30 but never out of “safe zone” about 40,, nitrites 0, and ammonia 0. At first I thought maybe they were hyper sensitive to nitrates, but again, they in not the danger zone and i haven’t lost a single other fish. IMO, based on my experience with my indoor tank, Angels and EB JDs are very sensitive but they are just fine. So far i’ve lost over 25 teen firemouths in 2 weeks. Not a single other fish has died. I should add that they aren’t the Giant Adults babies- they are just randoms I pick up at Petco like one a month bc i absolutely love them and adore their colors. They’re gorgeous fish.

Anyway, I wouldn’t have believed it if i didn’t see it with my own two eyes, but mom & dad (the giant adults) are quite literally killing every firemouth in the pond. I watched the adults swim around with smaller FMs in their mouths while the other fish tried to steal them. Again, not their spawn. Is this their version of population control? bc this started when the two groups of random babies got bigger. I need help bc i’m upset I can’t stock FMs anymore, but moreover I want to know why the two largest are killing all the smaller ones!!! and only the FMs!!! wth?! I’ve googled my butt off to no avail

 

[Niccobacci11]

First, please don’t release any fish from your pond or tanks into lakes or rivers. Unless your lake is privately owned and not connected to waterways. Native or not they have been with petco fish that may carry diseases. And especially with this newly frequent die off, you don’t want to transfer that to a lake.

For your question, it sounds like there is quite a few fish in this pond are they getting enough food? Maybe they took feeding themselves in there own hands. Also a lot of structures, rock piles and tree stump with roots are awesome to keep aggressive behavior down. Water changes will also help, they help with everything just about. Evidently you have a build up of waste since it used to be 0 now 30. Even though 30-40 nitrate is said to be “safe” it will still add some stress to the fish, so if one naturally gets sick it would be harder for it to rebound than in 5-10 nitrate water, and they could be targeting weaker ones. How is the pond filtered? Is it just through plants?

 

[rosiesfishpond]

thanks for the response!

firstly, the lake behind my house is completely private and doesn’t get water from anywhere. it’s actually almost dried up one year when we had a dry spell. it’s completely man-made and it’s only purpose other than “lakeside property”, that I can see, is to feed the sprinkler systems around the lake. it’s also a home to a lot of birds. I’ve read up on this and I know how dangerous releasing non-native species can be. Let me know if I’m wrong, but I didn’t think it could do much harm in a completely blocked off small lake.

Secondly, i feed them twice a day and a very healthy amount of flakes and sinking pellets. i specifically do this so they will be full and happy and not fight. so far it’s worked but this FM issue is brand new. I have a sneaky suspicion they are trying to have their own babies.

As for filtration, we have a huge pump that feeds to a big block box with 6 filters that i have to hose down weekly bc they collect all the sludge. there’s a man made waterfall near the filter for filtration and the water is crystal clear. there’s also a pipe that leads to a rock formation on the other end of the pond with a large water spout for optimal oxygenation.

I have started doing about 15% water changes once a week to help with the nitrates.

if the 2 biggest FMs are taking it into their own hands to get food (very doubtful because I purposely overfeed them in the fall to get them bigger for the winter), why are they only killing the smaller FMs? wouldn’t they kill any small fish? I see wrigglers in the pond time to time and there are even minnows that have been in there for about five years, along with Tetras, and nobody bothers them! I even have a school of mollies in there lol but that’s only because I had a crisis with the indoor tank so I had to put everyone in the pond so they didn’t die. but the mollies LOVE the pond. Lol the one male chases any female (big or small cichlid) around trying to mate. so far he hasn’t annoyed anyone bc he’s still there!

but the point is, they have no interest in killing any other fish but their own kind. knock on wood!!! I had a thought last night because they killed five more teenage FMs overnight (ugh so sad)… maybe they are killing them because they are preparing to have their own babies (hence the attitude problem) and want all the others gone? Is that a thing? I would take them out and rehome because they are GORGEOUS but they are so mean to their own kind, and they are so fast I couldn’t catch them to save my life.

Oh almost forgot, it’s a planted pond with lily pads year round but scarce in the winter so we have fakes to give the fish coverage other than a walkway that goes clear across the pond. it’s perfect to protect them from cranes. Also, i’ve spend a pretty penny on large castles (where the big FMs live) , log tunnels to hide, there’s also the rock formation they used to hide in before they got used to the birds and still use sometimes, and tons of other caves and hiding spots. Sometimes i think a fish died only for me to find it a year later all grown up. so they can hide very well. there are at least 20 hiding spots. I planned this out as best as I could. although clearly something is wrong.

I think I answered all your questions. Any more advice? It really bums me out because I started my pond with blood Parrots and FMs, both my personal faves, but I guess I can’t add anymore FMs at this point. any more advice would be extremely welcomed!!