Cichlid's Fins and Tail Turning Black

  • We are currently upgrading MFK. thanks! -neo
I agree with all of Toms posts.
The tank is too small to add anymore fish..... in fact...it will be too small for only 1 semi adult oscar very soon.
It usually takes 6 to 8 weeks to cycle a tank, cycling means building up a large enough population of beneficial bacteria in the filter and tank proper to handle ammonia and nitrite produced by fish metabolism, this takes time. And because your tank is overstocked for its lack of cycling, the discoloration may be the first signs of ammonia and nitrite poisoning.
If it were me, I'd be doing daily 40% water changes to dilute what I expect, is toxic amounts of ammonia and nitrite, until the proper population of good bacteria has grown, you will be able to determine this, when your API test reads 0.0ppm ammonia, 0.0ppm nitrite, and some nitrate.
By the way, all the good bacteria resides of surfaces such bio media in the filter, tanks sides, and decor, it is not floating in the water.
 
I'd get that test kit pretty quick if I was you. By the sounds of it you haven't let your tank cycle properly before adding your fish. The fin damage you describe could well be ammonia burn, if it's doing that to their fins imagine the damage it will be doing to their gills.

Until you get your kit home and are able to test your water, i'd do water changes galore. If it is ammonia related the water changes will dilute the ammonia making its easier for the fish to get through this traumatic patch. Be sure to add your seachem conditioner too, and observe their behaviour.
 
I’m m not going to mention the cycle of the tank as I believe everyone has touched on that as being the main problem of the tank.

The other problem that Duanes pointed out is that your Oscar will outgrow the tank...maybe even your planned 75g...you are very overstocked right now and you are struggling to maintain he toxins in your tank. My advise would be to return the Oscar or re-home it (unless you plan to get 100g tank for just the Oscar with no tank mates)

My honest suggestion would be to return all your fish, plan your stocking based on your current tank (not a future tank) and complete the cycle on your tank prior to add your planned stocking list.
 
  • Like
Reactions: RD.
I’m m not going to mention the cycle of the tank as I believe everyone has touched on that as being the main problem of the tank.

The other problem that Duanes pointed out is that your Oscar will outgrow the tank...maybe even your planned 75g...you are very overstocked right now and you are struggling to maintain he toxins in your tank. My advise would be to return the Oscar or re-home it (unless you plan to get 100g tank for just the Oscar with no tank mates)

My honest suggestion would be to return all your fish, plan your stocking based on your current tank (not a future tank) and complete the cycle on your tank prior to add your planned stocking list.
Thanks guys. I will re-home the oscars for 2 weeks as 100 gal+ tank works in progress and will be there in 2 weeks. Appreciate all your time and feedbacks.
 
Discoloration is most likely from ammonia burns.

Time to regroup, re-evaluate your stock list, and start a recovery plan as per Niki's suggestion.
 
  • Like
Reactions: Mohsin99
MonsterFishKeepers.com