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Tropheus Duboisi killing eachother off; how to move forward?

4K views 7 replies 4 participants last post by  noddy 
#1 ·
I have a 75 gallon aquarium that houses about 30 Tropheus duboisi alongside Julidochromis transcriptus and Synodontis petricola. These Tropheus have been in the tank for 2.5 years. They were only about an inch long, including tail, when I first got them. Up until the past month or two, I had not recorded a single death, but since then, I've lost three, and I just moved another into a hanging net box in the tank after finding him (or her) lying on his side in a fake plant this morning. He is now holding himself upright but is still resting on the bottom of the net box as I write this.

Aggression/stress, perhaps amplified by the tank size, is my theory for these deaths. I had witnessed fights numerous times over those 2.5 years but did not note substantial injuries, and certainly no deaths. They have laid eggs multiple times, though only one set was held to term. But in the past few weeks, at least four different males have been staking out areas which they have dug out little sand pits in, and aggression seems to have increased considerably. In the morning I'd wake up and find a fish dead with chunks out of its tail. This has happened three times in a month or two, and I fear it will not cease.

Given the tank size, I think the two possible solutions are either to greatly decrease the Tropheus population size or try to sell the entire population altogether. I don't know how to vent a fish and it sounds like a daunting task, so I don't know if trying to keep one or two males and the rest females will be a good idea, especially since I don't know if the females will just get attacked incessantly once they're part of a smaller group. I'm leaning toward the second option. FWIW, given how much I paid for them at my LFS as juveniles and how much I've seen them go for at this current size at the same LFS and on online marketplaces, I think I would make a profit even after costs of raising them, if I can find a buyer. I just want to know if the situation is salvageable.

For context, filtration is via a Fluval Fx6, which also contains Seachem Matrix. Water changes about 30% once every week or two. System has been running since mid-2016. The newest fish to the system were the Tropheus, and none died for most of the 2.5 years, so I don't think disease is playing a part (unless sudden bloat??). pH high 7s (haven't tested it in a while), hardness unknown, nitrates 30 or below for the span of the 2.5 years.

Any advice? Is parting with the entire Tropheus group the best possible move? Thanks in advance.
 
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#2 ·
679x said:
...Any advice? Is parting with the entire Tropheus group the best possible move? Thanks in advance...
I'm assuming that this is a 48" x 18" tank, and if so, that's too many Tropheus for a tank of this size, even for T. duboisi, which is generally the least aggressive Tropheus species. You've already outlined your options- either reduce the population down to 2-3 males and 10 or so females, or re-home the whole colony. Which of those options you choose depends entirely on whether you want to continue to keep this species. Good luck. :fish:
 
#3 ·
I will guess that it is bloat, brought on by stress. It sounds like they have now reached sexual maturity and the males are fighting each other and harassing the females.
30 Trophs in a 75g tank is a lot. I would also say that with 30 % water changes weekly that your nitrates are sky high.
I kept a couple of groups of 32 -36 Trophs in 120g tanks and needed to do 90% changes every week just to get the nitrates down to around 20ppm.
The best thing imo is to reduce the size of the group and maybe only have 2 males and 10-12 females in the 75. Easier said than done though as nobody will buy fish from a group that is dying off and not many people will be looking for male Tropheus.
Normally I would tell you to treat with Kanaplex or Metro but we are no longer able to buy these meds in Canada. No idea what we are expected to without meds but it is the reason I will not be getting back into Tropheus any time soon.
The only thing I can suggest is that you leave the lights off. I always found that was a great way to deal with aggression.
 
#4 ·
Thank you both for the advice.
The fish in the net box has passed. I only found him this morning after turning the tank's light on, and I shut them off again after putting him in the net box. The lights will certainly be staying off.
And maybe my nitrate test is off. I use the API liquid test kits. I've heard about their nitrate test being inaccurate and so over a year ago I started employing the popular suggestion of banging the nitrate test kit #2 on a hard surface repeatedly before dripping it into the test tube - not sure if that did anything useful.

I love my Tropheus but in fear of losing any more (prior to keeping the Duboisi, I had Tropheus Ikola and had a lot of deaths from bloat, though at the time I was able to treat w/ Metro) I think I will part ways with the genus. Probably best for them & me. In the meantime, this tank will get some hefty water changes and the lights will stay off, and hopefully I can stabilize the situation and keep everybody in good health as best as I can. I have no idea what to expect in terms of success in selling them. Thanks again for the advice.
 
#5 ·
So it's been 9 days and so far the colony has stabilized, i.e. no more deaths or visibly injured fish during that time. The tank is beside my desk so even though it is dark, I can see that there are territorial fights continuing between two particular large males in the centre area of the tank, and I just watched one of those males mate the day after I did the first ~60% water change (the day after my last post). The following day, though, the female didn't appear to be holding anymore, so I assume she ate the eggs. No breeding activity seen since, but I'm continuing with the larger, more frequent changes.

Now, if anyone has any advice on pricing or selling the colony, I would greatly appreciate it. I haven't gone about posting an ad yet and I don't really know what I should price them at. I think it'd be better if I sold the colony as one unit instead of selling individuals so as to not cause further disruption in the hierarchy of the remaining fish and also to not reduce the number of females in there, plus the fact that I'd have wanted to sell the obvious males first, but I don't know if it's going to be difficult to find a buyer for the entire colony or not.
 
#7 ·
Selling a whole Tropheus colony can sometimes be difficult because you need to find a particular kind of buyer, i. e. someone with a big tank, cash to spend, and a serious interest in keeping Tropheus. That said, if you price the colony right it will usually generate some interest, especially if there are dedicated cichlid keepers in your area. Don't be tempted to just take the retail price of small T.duboisi (~$15-20 each) and multiply it by your colony size, perhaps adding a premium for bigger fishes; this will make the asking price unreasonable. On those occasions when I have had too many of a particular type, I have actually given small Tropheus colonies away to experienced fish keepers rather than sell them to neophytes who would not give them the appropriate environment and/or care. I would never sell any of my Tropheus, juveniles or adults, to anyone who wanted less than 8-10 fishes unless they were experienced Tropheus keepers already. Good luck. :fish:
 
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