Sometimes there could be some complicating problems that may arise in our aquariums, which could take us unaware and worry us. I have received questions many times on social media from a few people asking why their crayfish seems to be turning black.
I quite agree that waking up in the morning and seeing your pet crayfish having black spots could be worrisome, so here are the possible causes.
1. It is Most likely they are black because of the texture color.
This might be an indication of shell rot.
This is common when a small lesion gets infected at the carapace layer.
So, what happens is that bacteria will get into the lesion and eat away at the chitin.
Normally this is perfectly natural and it’s quite harmless. It is a problem if there are a crap ton of sites for shell rot to occur.
But in that case, the danger is real in secondary infection… not the shell rot itself.
2. If your crayfish is turning black or having black spots, maybe it’s lacking some vital nutrients.
Diet is very important to every living thing, so when they lack some nutrients due to poor diet, this might happen.
You might want to start feeding your crayfish with quality food and a lot of vitamins.
3. Water Parameters could be the cause of this.
We all know that wrong water parameters or poor water quality could breed some random diseases which could hurt our pets.
If your crayfish is turning black, I suggest you test your water and know the level of chemicals in your water and try to control them if there are any.
The good news is there is every possibility that the black spots will disappear once the crayfish Molt.
So, I don’t see crayfish having black spots or turning black as much of a threat unless it is behaving very strangely because they are likely to come back to their right color once they Molt.
Again you might want to talk to your vet when this happens for medical advice and assistance.