In the wild, the loser gets to leave.
In our tanks, he can be toast, because losing isn't enough.
1. be aware of the territorial demand of the species kept. Ideally, double it, and you'll have a much easier time.
2. have a lot of cover for some species. Put in some vertical rocks: spires. These seem to provide a border for some species, and also a visual break or turn in a chase.
3. if you have a persistent individual, try taping a mirror to the glass: most crankiness is most aimed at others of the same species. This can let the cranky fish vent there, while the chasee recovers. This is also a good test BEFORE you add another.
4. do not add fish that look like other cranky fish---same shape and paintjob.
5. turn out the lights: this will often stop a fight on a newly added fish. Every lights on is a new morning and every day is a new world to a duck. They may forget the new addition is new.
6. remove the dominant to qt for a week. Let the new guy settle in. But not TOO long, or the dance may have a new leader.
7. Among first principles, look at aggression charts. Foster/Smith has one.
8. Understand that most fish don't want competition/fish that look like them. They're happy solo.
9. Understand that mated pairs of anything can claim twice the territory of one fish.
10. Add a 'dither fish'; for some tanks this works either for fish that are terribly shy and want somebody else to be 'up' and swimming before they come out of their holes---or it can break up a fight simply by having a grizzly bear walk through the bar fight. I had two Clarkiis that could be beasts---bit me bloody, and yes, they have teeth. I also had a blue velvet (neoglyptidon) damsel that was one of the pushiest. crankiest fish I've ever had...feared nothing except the Clarkiis. But also tended to waltz through the Clarkiis chases of the other damsels. I had a very lively tank, but nobody got bit. The dwarf angel was safe: all the stress was the Clarkii/velvet action. The lesser damsels were safe. The royal gramma was safe. What I had (novice) should have been fish chowder---but they all got along without killing each other. It's a difficult job---balancing tempers and fighting weight, but it is a tactic that can calm things down.
Above all else, watch your alkalinity: acid-burned skins and gills increase temper and touchiness---8.3 is a good middling level; watch your oxygenation---oxygen-short fish can get panicky; and have a big enough tank for the ADULT size of the fish you have. A two year old human shut in a closet KNOWS it's too small and panics---even if it's ample for his two-year-old shape. Just because a very young fish 'fits' doesn't mean he's happy about it. Always go by adult size---google it, species by species, and know your stuff.
In our tanks, he can be toast, because losing isn't enough.
1. be aware of the territorial demand of the species kept. Ideally, double it, and you'll have a much easier time.
2. have a lot of cover for some species. Put in some vertical rocks: spires. These seem to provide a border for some species, and also a visual break or turn in a chase.
3. if you have a persistent individual, try taping a mirror to the glass: most crankiness is most aimed at others of the same species. This can let the cranky fish vent there, while the chasee recovers. This is also a good test BEFORE you add another.
4. do not add fish that look like other cranky fish---same shape and paintjob.
5. turn out the lights: this will often stop a fight on a newly added fish. Every lights on is a new morning and every day is a new world to a duck. They may forget the new addition is new.
6. remove the dominant to qt for a week. Let the new guy settle in. But not TOO long, or the dance may have a new leader.
7. Among first principles, look at aggression charts. Foster/Smith has one.
8. Understand that most fish don't want competition/fish that look like them. They're happy solo.
9. Understand that mated pairs of anything can claim twice the territory of one fish.
10. Add a 'dither fish'; for some tanks this works either for fish that are terribly shy and want somebody else to be 'up' and swimming before they come out of their holes---or it can break up a fight simply by having a grizzly bear walk through the bar fight. I had two Clarkiis that could be beasts---bit me bloody, and yes, they have teeth. I also had a blue velvet (neoglyptidon) damsel that was one of the pushiest. crankiest fish I've ever had...feared nothing except the Clarkiis. But also tended to waltz through the Clarkiis chases of the other damsels. I had a very lively tank, but nobody got bit. The dwarf angel was safe: all the stress was the Clarkii/velvet action. The lesser damsels were safe. The royal gramma was safe. What I had (novice) should have been fish chowder---but they all got along without killing each other. It's a difficult job---balancing tempers and fighting weight, but it is a tactic that can calm things down.
Above all else, watch your alkalinity: acid-burned skins and gills increase temper and touchiness---8.3 is a good middling level; watch your oxygenation---oxygen-short fish can get panicky; and have a big enough tank for the ADULT size of the fish you have. A two year old human shut in a closet KNOWS it's too small and panics---even if it's ample for his two-year-old shape. Just because a very young fish 'fits' doesn't mean he's happy about it. Always go by adult size---google it, species by species, and know your stuff.
Last edited:
