Backyard Aquaponics
A place to discuss aquaponics

Hi,

About 4 weeks ago my son came home with 2 fish from the fair (don't get me started, I hate it I think it cruel & should be banned...... but I wasn't there)

One was already larger than the other, which I don't think they should have given him. I suspect maybe bigger one an ex breeder they wanted to get rid of, its 3" nose to end of tail and bigger than ones they usually give away?(Can they breed whilst still that small?) The smaller one (it looks like a sarrasa comet) is nearly 2" inc tail.

I had them in a temporary 5 gallon tank whilst other temporary 10 gallon I got my hands on was doing a fishless cycle. But after they recovered from their trauma and started to perk up in the treated amonia free water, the bigger fish started to bully the smaller one, nudge it, block him in a hidey hole etc, and the smaller fish was stressed and starting to 'lean' etc and clamp its fins. So out came bigger fish into the 10 gallon. So I have been trying to cycle both tanks on the go, checking stats with api tests kits. So far so good, with partial water changes levels have been kept very low, and added beneficial bacteria to to try and help things along.

Since both fish broke out in ich shortly after he brought them home (successfully treated with malachyte green and formalin, treated again after they left fish to make sure I got the free swimming ones) I assumed maybe the bullying was down to the little fish being ill and weak, as he did have the worse outbreak. So here we are 4 weeks later, I thought I would try and reintroduce the smaller fish into the bigger tank, but immediately the bigger fish started to nudge it and nip it.

So my question is this: Is this bullying, or could it have been attempting to breed if it was a breeding fish? And now they are separated again, would it be better to get company for the smaller fish and keep bigger one on his own? Or would the bigger fish cope if we got a similar sized goldie? (I will be getting a much bigger tank before I get any more fish )

I have kept goldfish and koi for about 20 years now. There does seem to be the occasional specimen which is more aggressive than the others. This can be trained out but takes allot of time and patience... And a short balsa wood stick or similar density material. Instead of training you could provide a larger tank and more fish for the bully to chase or a fish which is substantially bigger than the bully. If you have about 3 hours a day for a month they can be trained by taking a balsa wood stick 1/2 inch square, usually easy to find at hobby shops. Cut it to about 2 feet long and round of all corners and edges so there's no sharp edges. Start by getting comfortable tank side and make sure you have no distractions for this to work. Remove the aquarium top and any major obstructions. Now, with what we call "the beat stick" in hand feed your goldfish/ koi a small amount and observe feeding. At first notice of aggression toward other fish use the beat stick to surprise the offending fish with a gentle tap by quickly inserting the stick into the water and tapping it. Continue to observe fish intently for the next three hours and only use the stick when you see bad behavior. The surprise tap must come within seconds of the offense or it won't be understood. Make sure to remove the stick from the water immediately after taping so the goldfish doesn't have time to figure out what the tap came from. I have had fish that get it the first day and fish that have taken weeks. The trick is not to use aggression to train out aggression but instead to use surprise. The smaller fish, in your case should not be getting tapped and therefor stay calm. It is important that at least some of your fish stay calm so they aren't all just hiding.

Only tap immediately after aggression is witnessed and only once per offense!