It may or may not be algae. Many otos die with swollen abdomen. I lose about 1/3 of the otos after about a week, and about half of them die with swollen abdomen. I do have to agree that many otos are susceptible to MFD.Matty said:He seems to have alot of algae in his belly, as well as some red spots towards the tail...any ideas of what it could be?