Aggressive Fish

[Guest PaulAbbott]

Hello People - we would really appreciate some advice. When my partner and I bought our house a year ago, there was a sludge filled fish pond at the bottom of the garden - it was so weeded over the dog fell in it thinking it was solid. Anyway, about four months later we noticed bubbles in the slime and after scraping some of it off, discoverd quite a large goldfish living in there. We cleared out most of the dead branches (the pond is about 4ft x 6ft by about 3ft deep) but the water was brown. Last week we pumped most of the water into a couple of dustbins, caught the fish (and three frogs) and put it (them) in a dustbin, cleaned out the pond, but the fish (and the frogs) and the water back in, bought a filtre and cleaned the water. Fish seemed much happier, but we decided it must be lonely so today we went out and bought two similar sized (about 6 inch) fish from a reputable shop. Once they were properly acclimatised and released into the pond, the old fish at first seemed delighted to have company and they all swam around together having a lovely time - they seemed to be playing in the bubbles from the filter, and were eating, following each other everywhere and having a jolly time. However, now about 8 hours later the old fish has started really hassling the other two. It will stay on the otherside of the pond, for a while, and the two new ones stay quietly on their side, and then the old one will shoot around, barging into them and start really shoving and pushing until they try to get away, and then he chases them. If they stop he starts nudging at them until they try to get away again. He will then swim to his own side of the pond and swim back and forth in an aggrivated sort of way, until he will eventually zoom around and start the whole hassling thing again. Have we made a mistake introducing new fish? Should we remove the old fish for a while and re-introduce him so that he is the 'new' fish or will they just settle down? The new fish are not the same colour as the old one - although very similar in shape etc, the old one is bright orange, the new ones are a silvery green colour.

[scaring]

Hello People - we would really appreciate some advice. When my partner and I bought our house a year ago, there was a sludge filled fish pond at the bottom of the garden - it was so weeded over the dog fell in it thinking it was solid. Anyway, about four months later we noticed bubbles in the slime and after scraping some of it off, discoverd quite a large goldfish living in there. We cleared out most of the dead branches (the pond is about 4ft x 6ft by about 3ft deep) but the water was brown. Last week we pumped most of the water into a couple of dustbins, caught the fish (and three frogs) and put it (them) in a dustbin, cleaned out the pond, but the fish (and the frogs) and the water back in, bought a filtre and cleaned the water. Fish seemed much happier, but we decided it must be lonely so today we went out and bought two similar sized (about 6 inch) fish from a reputable shop. Once they were properly acclimatised and released into the pond, the old fish at first seemed delighted to have company and they all swam around together having a lovely time - they seemed to be playing in the bubbles from the filter, and were eating, following each other everywhere and having a jolly time. However, now about 8 hours later the old fish has started really hassling the other two. It will stay on the otherside of the pond, for a while, and the two new ones stay quietly on their side, and then the old one will shoot around, barging into them and start really shoving and pushing until they try to get away, and then he chases them. If they stop he starts nudging at them until they try to get away again. He will then swim to his own side of the pond and swim back and forth in an aggrivated sort of way, until he will eventually zoom around and start the whole hassling thing again. Have we made a mistake introducing new fish? Should we remove the old fish for a while and re-introduce him so that he is the 'new' fish or will they just settle down? The new fish are not the same colour as the old one - although very similar in shape etc, the old one is bright orange, the new ones are a silvery green colour.

Just a thought, don't know for sure, but could you have introduced females and your old fish was male?

[Guest PaulAbbott]

Hi Roni

Its a possibility. Does that mean its okay to leave them to it?

[Acupunk]

Based on your description, it doesn't really sound like breeding behavior. When males chase females they will relentlessly follow around behind them, nosing around their tails. The impression that you get is of a very persistent suitor, not so much aggression. Your description sounds like a fish that is used to being the King of the Castle and doesn't necessarily like the idea of sharing his space on a long-term basis. Is your old fish still behaving aggressively? Are the new fish single tailed goldfish? I ask because silvery-green goldfish are pretty unusual.

[Bob the Goldfish]

I ask because silvery-green goldfish are pretty unusual.

Or they are wild fish.

[Acupunk]

I ask because silvery-green goldfish are pretty unusual.

Or they are wild fish.

True -- all wild goldfish are silvery green. Very young goldfish are also this color. I just have never seen adult silvery green goldfish for sale in a store.