One fish obsessed chasing another, why?

[Esquire]

I have 6 juvees 2.75 - 3.25" in size in one tank, 4 red spotted greens and 2 Blue diamonds.
1 of the blue diamonds is the runt of the tank but it keeps chasing the other BD around the tank. Nips at it's side. Never chasing other fish, just the one blue diamond. I don't see any damage on the fish.=, but I can see the blue diamond being chased avoiding the chaser.

In the fish world what does this mean?
Courting?
Fighting?

[CraigG]

I have 6 juvees 2.75 - 3.25" in size in one tank, 4 red spotted greens and 2 Blue diamonds.
1 of the blue diamonds is the runt of the tank but it keeps chasing the other BD around the tank. Nips at it's side. Never chasing other fish, just the one blue diamond. I don't see any damage on the fish.=, but I can see the blue diamond being chased avoiding the chaser.

In the fish world what does this mean?
Courting?
Fighting?

I think its just the fish establishing pecking order. I have one that is still doing it and its been about a month of having them. I just added 3 more on Monday and he started doing it the the newbies in the tank.

My German Blue Rams do it to each other as well.

[Apistomaster]

I think you answered your question. Discus always form hierarchies based on relative dominance. At your fish's size that is based on size. Later on, as they begin to form pairs, then the pecking order becomes more complex as a pair will usually dominate over any other discus sharing the tank. Allowing enough room and some cover are usually your best bets to keep a relative peace.

[bs6749]

I have a feeling that the "runt" that is being described is actually a fish that is older than the rest but is stunted. Do you have any pictures of your fish?

[cquann]

If this go on for more than a week or 2. You should add more fishes now...or else your fish will either stop totally stress and stop eating.<<<<result will be fetallity soon...(my own experieced When it stressed then ur done deal, even though i do about 60% of WC everyday would not help) ADDing more fishes i think will be the best ideal... GL brother.

[Esquire]

Well the runt isn't stunted, he is growing fine but he is the smallest of the group, not by much.
All are eating like pigs.

This looks like fish being fish to me. Maybe even love. If it continues, I may put a divider in for a for a week or so. I will be adding 2 fish to the tank in a month or so.

[krazykat]

I think your runt needs to see a fish psychologist for its "Napoleon complex!" :p

[Esquire]

Agreed,
I know a few people with the same problem also.