A few months ago I began noticing these weird, irregular black blotches on many of my fish including festae, salvini, etc. I have no idea what it is. It's obviously not part of their coloration and they didn't have it when I bought them.... but they behave normally, eat normally and show no other symptoms... the spots come and go on their own. My water parameters have been stable Ammonia 0, Nitrites 0 and Nitrates 5 ppm for months now.
Diet is krill, bloodworms, nls pellets, omega one pellets, live crayfish, live shrimp, live red wrigglers.
This is what it looks like, my fish have a lot less spots on them but you get the point


I've been researching and found a few possible causes:
- the black spots are actually healing injuries - would make a lot of sense since I house different aggressive species together and they do fight.
- harmless black spot disease from eating farm raised snails (snail eats bird poop, fish eats snail... cycle ends unless a bird eats your fish and poops in your tank). This would make sense too since I keep a lot of farm raised snails (mostly nerite) and every now and then I find empty shells in the tank which means fish are eating them.
- fungus (?)
- diet
I also use seachem stressguard that supposedly acts like a "band aid" by binding to exposed wounds. This could be the cause too?
Any input? thanks in advance. I have been researching for months and haven't been able to find a solid answer. None of my fish has died or acted sick.


Diet is krill, bloodworms, nls pellets, omega one pellets, live crayfish, live shrimp, live red wrigglers.
This is what it looks like, my fish have a lot less spots on them but you get the point


I've been researching and found a few possible causes:
- the black spots are actually healing injuries - would make a lot of sense since I house different aggressive species together and they do fight.
- harmless black spot disease from eating farm raised snails (snail eats bird poop, fish eats snail... cycle ends unless a bird eats your fish and poops in your tank). This would make sense too since I keep a lot of farm raised snails (mostly nerite) and every now and then I find empty shells in the tank which means fish are eating them.
- fungus (?)
- diet
I also use seachem stressguard that supposedly acts like a "band aid" by binding to exposed wounds. This could be the cause too?
Any input? thanks in advance. I have been researching for months and haven't been able to find a solid answer. None of my fish has died or acted sick.

