Have you noticed that your pleco has small holes in its dorsal fin?
A healthy pleco should not have holes in its dorsal fin, so this is something that you should be a little concerned about.
Fortunately, it’s a relatively simple problem to fix and return your pleco to good health. You can also just ignore it as plecos are extremely tough fish and can survive a lot.
Anyway, the cause of the holes in your pleco’s dorsal fin is from too much organic waste in the water. This causes small holes to form in the membrane on the fin.
Curing Holes in a Pleco’s Fin
The first step to solving this problem is to lower the amount of waste in the tank – you want to fix the cause and not the symptom.
The first step in this process is reducing the number of fish in the aquarium, especially ones that produce a lot of waste like plecos. Remember, plecos do not eat poop, so you still have to vacuum your tank. I recommend a daily vacuuming of the substrate to clear out the waste. Frequent water changes will also greatly reduce the amount of waste in the tank.
Too much waste in your may also indicate too much ammonia in the tank, which can cause white patches on your pleco.
You will notice that over enough time the holes will start to get smaller until they eventually disappear.
It’s not a difficult problem to solve in my opinion, but it does require a little effort and good tank maintenance.
Closing Words
That covers it for why your pleco has holes in its dorsal fins. It’s almost always because there is too much waste in the tank and the membrane on the fish’s fin has broken down forming some holes.
It’s easy enough to fix by reducing the number of fish in the tank, vacuuming the tank on a daily or near daily basis, and doing frequent water changes.