Help With Serpae Tetra Fin Nipping

Serpae tetras are a midlevel species of freshwater fish belonging to the family Characidae. These fishes are typically red in coloration with a black diamond on their flanks and black tips on the anal and dorsal fins. Like all tetras, serpae tetras are a schooling species and should be kept in groups with at least six of their own species. Even in schools, however, serpae tetras are likely to become aggressive and to engage in fin nipping. While you may not be able to completely eradicate this harmful behavior, there are a few things you can do to minimize it.

  1. What is Fin Nipping?

    • "Fin nipping" is a term aquarium hobbyists use to describe the behavior of certain species that tend to bite the fins of other fish. Tetras in particular are known for displaying this behavior, especially when they are not kept in schools of adequate size. In addition to literally nipping at the fins of other fish, serpae tetras may also chase other fish around the tank. Though this behavior is often limited to the same species, tetras have been known to nip at long-finned species of fish like angelfish and certain species of danio.

    Why Do Serpae Tetras Nip Fins?

    • When kept in schools, serpae tetras are likely to establish what is called a "pecking order." This term is used to describe the hierarchy assigned to the fish in the school when it comes to feeding. Typically, the dominant male of the group will take the highest position in the pecking order -- the center of the feeding area where he will have access to the most food and to the dominant female. Fin nipping occurs most frequently during feeding as certain fish in the school fight for a higher position in the pecking order. If new tetras are added after the school has already been established, these fish may find themselves at the bottom of the pecking order and frequent targets of fin nipping.

    Preventing Fin Nipping

    • While you may not be able to completely prevent your serpae tetras from fin nipping, keeping them in a large school is the best way to lessen the severity. In larger groups, it is less likely that a single fish will become dominant and the tetras in the school may be less aggressive overall. Keeping your tetras in a large group is a good way to ensure that the fin nipping is contained within the group and is not directed at other fish in your tank. If your tetras seem to be targeting the other fish in your aquarium, consider removing the targeted fish from the tank. In order to minimize the amount of fin nipping directed toward other fish, do not keep any other midlevel fish in the tank with serpae tetras.

    Consequences of Fin Nipping

    • Within the school, excessive fin nipping could result in one or more fish having difficulty accessing food. Fish that are unable to eat may become malnourished and could become more susceptible to disease. Additionally, fish are likely to become stressed by the aggressive behavior of their tank mates and could decline in health as a result. Another potential consequence of fin nipping is fin rot. Damaged fins are susceptible to the bacteria that cause the common aquarium fish infection known as fin rot. This disease can be very serious and could result in the destruction of the entire fin.