knighty76

Hey all,

Would appreciate some advice for how best to deal with a particularly aggressive guppy. I've got 4 male guppies in my 16 gal tank and initially they were all getting along very well, but now one particular guppy has become very agressive towards one other particular guppy. He chases him constantly, nipping at his ventral fins, especially on his left hand side. It's got to the point where his LH ventral is less fin-like and more pink bloody stump-like. There are also a couple of splits in his caudal fin.

The victim is a large fancy tail, biggest out of all in the tank, and it was described as leopard-tailed in the shop which would seem to make sense.. it has white and pink and orange colouration to the tail, and a silver body with black markings. The bully is a less fancy yellow lad, smaller tail with only a slight snake skin pattern. He follows his target all day, chasing in circles and nipping endlessly at the poor fella. The two other guppies seem to get away with it.. one is very small and is largely ignored, the other is the real daddy in the tank and doesn't take any rubbish from the yellow beast.

I've tried isolating the bully in a breeder net for a couple of hours and even overnight, but so far no difference. Within a few minutes he's back on the rampage. The crazy thing is that when he's not being nipped at the victim tends to follow his tormentor around like a lost puppy!!

Were it not for the damage I'd be less worried. Any advice would be appreciated. I've had the guppies for a few months now and would be surprised if the LFS would want him back.

I don't have a seperate tank, just a breeder net. Tankmates are Neons and Corys... no bother there. Water parameters are all good, they get regular water changes and I keep the temp at around 78 deg F. I feed fish flakes with the odd freeze-dried bloodworm treat. There has been some illness in the tank previously... suspected fin rot treated successfully with Melafix. Don't know if this is relevant.

Ideas welcomed!! Although I'd point out there probably isn't room for any ladies in there, and certainly not enough for fry!!

Cheers all,
Rich.

Nick G

Tough one. I had the same problam with one of my Platys, I removed her and put her in my Oscar tank. They're not big enough to eat her yet but they chased her for about 2 minutes before I removed her. I then put her in my quarintine tank overnight and put her back with the others in the morning. Since then she's been fine, no more aggressive than any of the others. If you've already tried removing him and it hasn't worked could you exchange him at the LFS if you explained the problem?

isis

Yeah that is a tricky one. Nick's platy surely learnt a good lesson LOL!
It's no use having him in thank. He might kill the one he is bullying and move on to the next victim. Do you really want that?
I'm sorry that I can't give you any advice - I also would have told you to isolate him for a while... but since you've done that and it didn't work... tough one!

Wyoming_Bound

My male guppies never fight like that but the have lot of females. put the bully in the breeder net for a for day and move the tank decor aroond them put him back in see how it goes. if that fail ship it to nick so he can have os oscars chase him for a few mins then ship him back to you. lol good luck.

knighty76

Thanks for the replies. Just pulled him out of 12hr solitary confinement and within 2 mins he's pestering the life out of poor Louis (the victim).

Would changing the temperature at all make any difference? If they prefer to breed at warmer temps, perhaps the males get more feisty when it's warmer.. could lowering the temp a couple of degs make any diff?! I've got it running a wee bit high at the min, around 80 deg F.

Also wondering if there would be any benefit to adding another guppy? I guess this could alter the dynamic in the tank? Or would this be throwing oil on the fire?

Cheers all,
Rich.

fishyuser63

Ideally you would want 2 or 3 females for everymale. Adding more guppies could help spread out the aggression, therefore reducing the stress on a particular fish. Be sure not to overstock though. In my experience, male guppies will relentlessly chase tankmates. I had 3 problem males in a community tank and they chased a swordtail and 2 platys to death before I could move them. I traded two of the males for females and the remaining male settled down. Hope this helps.

knighty76

I have a new theory!!

It seems that the poor fella getting all the hassle is now being chased by most of the other guys. I'm wondering now whether the randy little bu*gers are mistaking him for a girl, as he has some quite striking black markings on his silver body which become quite prominent at certain times of the day. I'm no expert, but I'd say that one of the markings is fairly close to where a female guppy would have the gravid spot near it's anal fin. Perhaps this is sexual harrassment?!!

Does this seem feasible? I'm not certain of any of this.. he has the largest, fanciest tail of all my guppies which I understand to be a male trait, yet the markings could be a problem?

Thanks all,
Rich.

Nick G

I would say not. It sounds to me like he's just being bullied. If he has a large tail it's unlikely that they think he's a female. It could be that the tail is the problem, and he's being chased because it's so big.