I wanted to follow-up on the previous post, The Julidochromis regani nursery. As you can see in the photo in that post (and above), I have some black beard algae (commonly referred to as BBA) growing on the rock structure. I have posted about this algae and its cousin, blue green algae (BGA), before.
Anyway, many people despise BBA in their tanks, or any algae for that matter, because it can be unsightly. This algae doesn’t bother me unless the tank is planted or the algae is out of control. The photo above shows BBA growing on some rock work in a 75g Tanganyikan community tank. This tank has no live plants, and the BBA is not out of control. While I do agree algae can be unsightly, in my case its more beneficial than unsightly. The BBA traps small food particles, which allows my julie fry to remain mostly hidden yet still be able to eat.
Algae can serve many beneficial purposes in tanks. As I mentioned, it not only traps some micro nutrients for fry but, if dense enough, it will also serve as shelter, giving fry and smaller juveniles places to hide. Furthermore, algae will consume nitrates. Contrary to what you may have read or heard, BBA is not harmful to fish, including cichlids. Where you need to be careful is when the algae gets out of control, especially if you have live plants. Algae does compete with plants for nutrients and the algae can overtake plants, effectively choking them out over time.