Mayhem in the tank - Breeding Pair had a fallout?

[Sasha]

Help! I have a 37 gallon tank with 4 young adult discus. (I bought them all at the same time as 2.5 inchers back in mid-Feb.) Two of the four became mates and I witnessed the most adorable love affair. They have laid/fertilized eggs 4 times (once I got to witness the entire process), but the eggs have not developed, most likely due to the hardness of my water. (I have an RO system, although I do not use the RO water in the tank, and at some point in the future I would like to get the water parameters suitable for egg development; however, I am not ready to get into the "raising babies" activities just yet.). During the courtship and egg laying/fanning/watching processes, it became apparent that I have at least one other male ("Cobalt"). While the mated-pair male ("Scrib") was fertilizing, Cobalt displayed his fertilization tube and clearly was wanting to get into the action. Scrib, of course, would not allow it and they had a bit of a physical tiff for a couple of days.

My dilemma: it appears that the mated pair has had a falling out (they are no longer demonstrating the loving behavior), and now all 3 of the other fish are ganging up on the mated-pair male ("Scrib"). I don't know what to do. They had Scrib cornered and were picking on him. Worried for his safety, I created a home made tank divider with 1" netting in a rigid frame that allowed full flow of water and food between the 2 halves of the tank. I separated the mating pair from the other two. Interestingly, they all four hung out near each other on their respective sides of the divider, and Cobalt tried voraciously to get through the divider. The female of the mating pair seemed to be dominant over Scrib in their half of the tank. But all four fish really seemed miserable and uncomfortable. The divider was in place for 3 days. Yesterday when I did a water change, I removed the divider. Today, they are once again all 3 picking on Scrib, and Scrib is showing his "stress bars" almost constantly. I am worried about his health (pecks and fin nips from the others, although I do not see any real physical damage) and the stress of being the outcast. They have him in a corner and all three will peck at him. If he ventures out, he is chased back into the corner.

Questions: Should I put the divider back in and separate Scrib from the rest of the fish? Will being picked on truly be detrimental to Scrib's health? (The pecks from the other fish do not seem to be damaging scales or flesh, but do fish have mental and emotional health in addition to physical health like we do?) Should I leave them alone and let them work it out? The situation is causing me much duress and stress, as I feel for these creatures who are in a captive environment with no place to run away to safety and get away from abuse. Do you think the mating pair will continue to be a "couple" after this demonstrated behavior?

Your help and advice is greatly appreciated. I am truly confused as to what I should do to resolve the mayhem in the tank.

[Keith Perkins]

This is probably a good example of why folks say you should have at least a 55 gallon tank for discus and 6 fish to spread the aggression around. That observation doesn't help you out at all though. Fish can literally be picked on to death, but so far it doesn't sound like your situation is that serious. You haven't described the inside of your tank at all, so my first question would be is there any cover available for a picked on fish? A few artificial plants strategically placed in a corner or something I find can do a lot to help in a situation like this. I have a pair that at times has had battle royals right after laying eggs, and the plants in the corner helped there.

You could also put the divider back in with a "pair" on each side of it, but I'd be reluctant to separate one fish all by itself. These are community fish and one by itself is not going to be happy either. The other option is to do nothing and hope for the best, but I'd personally be reluctant to do that for fear things get worse some day when you aren't home and you really regret that decision.

[Sasha]

Thanks, CozyKeith, for your reply. I have a bare bottom tank and yes, I have a few large plastic plants in it to provide places for protection. This doesn't seem to stop the other fish from "finding" him, of course.

Regarding your comment on a larger tank and more fish, this is my first Discus tank. I did do my homework before purchasing and I recognize that I went on the smaller side. I was frankly afraid of going bigger, because I did not know how I would handle the large volume water changes and the necessary water staging (circulating & heating of the water to prepare it). Regardless, what baffles me is that they got along rather well before this mating-pair "fallout". Sure, I'd have the occasional chase and peck, but it was pretty evenly distributed and short lived.

When I had the divider in place, I did have a "pair" on either side: the mating pair on one side (the side where they typically laid the eggs), and the other 2 on the other side. Given that the holes in the netting were about an inch or so, they could fully see each other and I was thinking (perhaps ignorantly) that this would still give them the sense of "community" that they need.

I'm wondering what might have triggered this all-of-the-sudden, aggressive behavior from all 3 towards the one male. And what are they trying to accomplish via this behavior? Is the female wanting a new/different mate? Could Scrib (the one they are picking on) be in ill health and thus they are picking on the weakest one? (although frankly he does not appear to be in ill health and he is one of the largest in the tank)

[Keith Perkins]

I only had a pair in a 29 when I had the problem and the plants worked, this situation is certainly a little different. Maybe a few more plants would help, but hopefully someone with the exact same experience in the past will come along with a suggestion. I age water in rubbermaid brute 44 gallon trash cans. All you need is a single heater and a single airline in it to properly age the water. I zip tie the airline to the heater cord near the heater to keep it at the bottom of the reservoir. One trash would allow you to do up to 80% WCs daily, which is way more than you need, so not quite sure what your concern was. Perhaps you don't have a spot for the trash can.

When spawning starts all the dynamics in the tank can change. What use to be the most docile fish in the tank can become the most aggressive and vice versa. The holes in the divider definitely help with the sense of community, no ignorance on your part there. The point I was trying to make was I'm not sure that would work as well if you isolate one fish and since things seem to work when you separate them in pairs if you decide to separate them again I would go back to the same situation.

Can't tell you what the other three are trying to prove, typical discus I guess. I wouldn't think they are picking on the scrib because it's unhealthy, but continued abuse by the other 3 could end up making it that way.

[Matt0matic]

I've had females leave their current mate for a different fish in a community tank before; I didn't do anything to stop it (added some salt and an oxidizer for a split fin) and eventually the harassing stopped after a week. This was in a 65 gallon with 6 fish. If it were me I'd treat any wounds appropriately and leave it be unless it is getting completely out of hand.

I have read that rearranging the scape might cause for the pecking order to get reestablished and the fish that is getting picked on can end up somewhere other than bottom of the totem pole. But there always has to be the low man..

[Sasha]

Thanks to all for the replies. I truly appreciate it. Good news is that things do seem to be calming down a bit, although Scrib is still getting more than his fair share of "attention" from the others.

To answer CozyKeith's questions about the tank size and water, my considerations were for both the space/location for the tank itself so that we could fully enjoy the fish (the tank is in the eating nook which is an extended part of the kitchen / hearth room combo) and for the location of the water staging bin, which (you were right) I did not want to have sitting out in the open. I built a low, rolling cart on which to keep the water aging bin, so when it's time for water changes I roll out the bin from the nearby laundry room. The bin (which holds about 28 gallons) weighs over 250 lbs. I'm a small female and can roll it by myself with no problem, but I couldn't imagine going too much bigger.

Again, thanks to all for insights and observations shared.