Why do compatible fish sometimes fight?
Written by
John Williams
Reviewed by
Prof. David Walsh, Ph.D.Compatible fish. These are sometimes indicated on a chart as compatible, but they will start fighting. The compatibility chart cannot always predict it; there are hidden reasons why, - A fish is not always a fish! Each fish has its own personality. - A small problem in the environment can become a small monster. - Fish are aggressive in a breeding state. - It's a crazy world out there.
Individual Personalities
- Fish develop unique temperaments like humans
- One betta may tolerate tank mates while another attacks
- Observe new fish behavior during quarantine periods
Breeding Seasons
- Hormonal changes cause territorial aggression
- Cichlids guard nesting sites aggressively
- Separate breeding pairs during spawning periods
Environmental Stressors
- Insufficient hiding spots increase conflicts
- Overcrowding triggers food and space competition
- Poor water quality escalates aggression
Territorial disputes between non-combatant fishes are occasionally causes of a fight. Decorations or plants outline the territories of fish. As new arrivals invade these spaces, defense is compromised, potentially leading to conflict. Change the position of the rocks and driftwood weekly. Scatter pieces of broad-leaved plants about to lend variety and obstruct the view.
The breeding seasons make even the tamest fish savage, so that cyprinids, for instance, will ferociously guard their eggs against every intruder. The male betta, for instance, will flare at all tank mates that come near the bubble nest. Always place a pair of breeding fish in a separate tank to spawn in and return them to their original quarters when the fry have become free-swimming.
Environmental Factors These factors make aggressive fish more competitive. Small and overcrowded tanks typically contain a higher fish density, thereby increasing competition for food and oxygen. Pollution of the water (ammonia and nitrite) makes fish irritable. Test results weekly. Water should be changed. Filtration systems should be working optimally. Allow one gallon of water for each inch of adult fish.
Recovery protocol (if fight starts, the easiest antidote is: gradual moving of aggressive fish to quarantine, partial water change to dilute the stress hormone the fish excretes, dim the lighting for 48 hours (so they can barely see if you show up), Indian almond leaves for the calming tannins, wait until their behavior returns to normal before introduction).
Read the full article: Fish Compatibility Chart Ultimate Guide
