OK - so I submitted to impulse this afternoon. I was in my LFS selling some fish and saw a lovely looking Juvi Tiger (about 6"). I currently have a single Tiger in my 6' (500L) tank and have been thinking of trying to get a second Oscar. My existing one is about 6.5 - 7".

I know it can be hard to add a second Oscar and that normally you should get several and wait to see which ones pair but I wanted to give it a go.

All seemed OK at first then occasionally my original Oscar would nip at the flank of the new one - it hasn't done any damage and it doesn't do it all the time.

I have the new one on a sale or return basis to see if they can get on but what I don't know is if I am going to have a problem or not.

Is this simply establishing the order of the tank or may it lead to more? How bad does it need to get to know that one of them has to go? If they are not compatible would one be constantly harassing the other?

It's night here now, the tank lights are out and all seems peaceful.

Thanks for any help,

Barry

It is just a case of seeing how things go, with a dog or cat, you normally know whether or not they get on with the other animals of the same species, however it's impossible to determine this with fish, it will either work, or it won't.

A little bit of banter isn't going to cause any problems, however if they take a complete dislike to each other, or one does to another and you start experiencing serious aggression where injuries are being caused on a regular basis then you may have to rehome one of these fish. Rearranging the tank sometimes works so that may be worth trying. Sometimes if a fish has been there longer than another, it may well have claimed as its territory and not appreciate another fish invading its patch. However, if you make things look completely different, this can sometimes create a situation where the environment is almost new to both of them.

Thanks Boss, I like your suggestion of moving things around to change the territory. I will probably give that a go tomorrow.

Mostly I was looking to see what constituted a serious problem and from what you say I don't think I have anything like that at the moment, so fingers crossed.

I added one who was about 2'' smaller to my tank a while ago..there was definitely a period of chasing and fin nipping for awhile but nothing too serious...Now they're inseparable. It's strange but to be honest I really don't see one behaving as the 'leader' or 'dominant' of the pair...so I don't know if that was established or they simply became 'used' to one another.

I'm thinking I got lucky and got a male/female pair.

One fish hiding all the time and especially not eating is a serious problem

If one fish is getting injured real badly then that is a serious problem too. You can ignore small little injuries like small nips to the tail or a couple bumps to the side.

If you are not sure then post a pic on here and we can tell you if its bad

I will post a pic as soon as I can take one to show off the new Oscar but there is no damage to show. The new one was eating quite happily this morning although there was still a bit of bumping going on at times.

I thought I would give an update on how things are going.

After two days I got up to find my original Oscar had a bit of a scrape on its head and thought it had bumped itself but I now think this was done by the new Oscar.

Most of the time both Oscars swim round together with no problems at all but every so often the newer (smaller) Oscar will have a bit of a go at the original one who then seems to back away. It's fascinating to see how dominance has changed round completely.

The new Oscar is eating pellets very well but won't touch the beafheart I give the original Oscar. The original Oscar seems to be off his food though - he went for two days without eating then ate as normal the next day but yesterday didn't eat again.

There don't appear to be any real battles - like I said, they mostly swim round together quite amicably.

johnnyphoenix wrote:


how big are your oscars? have they bred yet?

introducing new oscar in the tank is a "hit and miss", same with the oscars
that grows together. my Survivor and PinHole had to separated because injury
shows dangerous level already: swollen mouth, damage gill cover plate, and body
scrape. Survivor is now with the aro tank while Pinhole is with the other 2 tiger
oscar at 110g tank. this weekend, i am expecting the delivery of 6'x24"x36" tank.

i concur with delboybully..if one is hiding and always at the bottom, that one
needs attention before things get out of hand.

Neither is hiding, they both swim round the tank fairly constantly, either alone or together.

okey then...that is a good sign. congrats and enjoy watching....