Mature Cichlid Tank Split...DISASTER!!?

Question

Hey guys. I'm not really asking a question, just sharing a story.

These things happen to the best of us. My track record with fish is flawless, I lose very few fish as I'm all about live plants and making my tanks virtuallly maintenance free. I have a long running 29 gallon that only gets a 1/3 water change every 3-4 months.

I have a full time job and then some running my company and employing about a dozen people at the moment, but I always seem to find time to "breed" fish. I'm really no breeder, I just keep my nitrates so low in my tanks that things just kinda happen. I grow the fish out and sell them to the LFS's. It's been years since I've paid for anything at a fish store, I have so much credit from selling them fish :)

But...I'm in the middle of a really rough 48 hour stretch. I'll share my painful story, hoping that it will help others.

I have (almost want to say had) a beautiful 150 gallon Cichlid community tank where I housed 4 breeding pairs, 2 MD Pleco's and 12 Silver Dollars. They have been together from 1.5" to 3" and they are (were) my prized breeding pairs.

I have 2 pairs left, one of which I doubt will be a pair when I get home tonight.

They were all between 12-15 months old, so they were big fish...but not adults.

I decided it was time to split the tank up as my Black Tiger Oscar was starting to get picked on, despite bing the biggest fish in the tank and after a year plus of peace. They were just getting too big for a 150, but I have so many tanks that I was never worried about it.

I moved the Green Terrors and Midas Cichlids to the 120 gallon tank along with 6 Silver Dollars. They are doing great. I moved 2 Aquaclear 110's from the 150 to the 120 so that they had the same bacteria. I half filled the 120 with old water from the 150 and matched the temp exactly.

Everybody in the 120 is doing well.

Everybody in the 150 is dying...Even after a water change and enough Prime for about a 400 gallon tank. Zero Ammonia, Zero Nitrite and sub 10 ppm nitrates. Nothing out of the ordinary, my typical good clean water. Running a single Fluval FX5, so I have 400 gallons of filtration in a 150 and I use floating plants to control my nitrates as Cichlids won't let you grow plants.

I had 12 Silver dollars. 8 Red Hooks and 4 Spotted which were growing much slower.

I was shocked when I found the 2 remaining Red Hooks floating upside down the next day, one dead and one breathing. The 4 Spotted ones were ok and still had their spots. I figured ok, they missed their buddies and the stress killed them. My bad, I went 6 & 6 as modern theory would suggest.

I woke up this morning to find 2 Spotted Silver dollars dead on the bottom and....Gulp...My prized 12"+ Black Tiger Oscar dead on the bottom. One of my Jack Dempseys is acting strange and the Albino Tiger Oscar of course is sulking. The 2 Pleco's are fine as if nothing happened.

My only explanation is that the bond these fish formed from living together for 13-14 months was much stronger than I would have thought. The Stress killed them. I can't come up with anything else. There was no chasing, no thrashing. Just scoop, walk 5 feet and drop.

I expected issues with the fish I moved, not the ones that were left in the tank.

I'm really torn up right now, I'm expecthing to go home to a dead Jack Dempsey. I expect the remaining Albino Tiger Oscar and Jack Dempsey to also pass. I will keep the water as perfect as I can to prevent it, but I'm not working against a conventional disease.

So...I will leave you with this.

The new school theory where you can raise a fish in a tank that's too small for them and just move them at a later date, not true. I knew I needed to split the tank up before they became adults, but I was always able to keep them happy, healthy and the nitrates well under 20-25ppm.

I can't offer up a reason as to why this happened.

I'm not going to replace these fish. I may decide to use this as my exit from breeding.

Maybe it's time to just focus on my reefs and move on from freshwater...

I raised that little Tiger Oscar from 1.5" to approx. 13-14", he was my boy. He always swam up to the glass to beg me for food. I was able to hand feed him and I was able to pet him on his head. Amazing personality...

It sucks when they die. I just couldn't replace him. Time to move on.

Really bummed out. Sometimes you make all of the right moves and things still go bad :(

Answer 1

Awe...so sorry for your loss :( I hope all fish people read this and learn....I feel for you!

Answer 2

Sorry for your loss. I would suggest a larger water change to save any fish you have left. The separation is not likely what is killing them, but the netting of the fish might have released some hidden toxin in the substrate when you caught the other fish.



What is your pH?

Are you sure the temp is ok? (Sometimes in the commotion of netting the other fish it can get cracked or damaged and electrocute the remaining fish or overheat the tank.)



Also just the mere stress of netting and chasing the other fish can impact the other fish in the tank and might be part of the problem as well.



So, check the heater, do a larger water change and gravel vac. Also stop using prime and other chemicals to alter the water as they use oxygen in their reactions and you might be overdosing and suffocating the remaining fish!

Answer 3

the symptoms and timing say shock from a larger than usual water change,

perhaps a loss of biologic filtration because of the filter change

or accidental poisoning

or the change in the stocking caused a spurt of aggression that was previously not a problem because the fish could push around or beat up the large tetras.