Aggressive guppy - nothing seems to work.

[Torkelgutt]

Setup: 45 gallon tank, scarcely populated. 2 male guppies, 4 female.

(Others: 8 neon tetra, 2 mollies, 4 platies)

One of my male guppies have been acting aggressive for a while (he was fine for several weeks/months after I got him). He keeps chasing around my other male guppy, as well as the platies. I strongly suspect he was the reason one of my previous male guppies died, as that happened shortly after he started acting aggressive.

I've tried all the tricks I could think of:

I've isolated him in a smaller tank (with a divider between him and a betta) for a week or so. I've had him isolated in a bowl all of his own. And I've even tried keeping him in a breeder box in the main tank for a week or so.

Before putting him back with the others, I've rearranged my tank in the hopes of making it feel like a new territory. And there's plenty of plants for my fish to hide in.

Still the result is the same: Every time I put him back in, he's back to chasing and nipping at the other fish within minutes - and he doesn't let up at all. I have no doubt he'll stress some of them out enough to kill them if I keep him in there.

Are there any other ways of dealing with this guy that I haven't thought of, or is he doomed to a life in solitude?

 

[V227]

I'm not really your go to guy regarding guppy information, but I suggest you shop around for one really big, extra large male guppy and maybe two more females. Make sure the new male is solidly built and capable of dishing out plenty of guppy smack down. Lol.
Good luck, I'm sure things will level out soon.

 

[Angellove78]

I'd rehome him. Find a fish store to trade him into. Or free to good home. A bully in a tank causes a lot of problems, head aches for you more than anything. Sometimes it gets to be too much worry. I have a black male Molly and 3 girls, and he's got them all to him self. Loves everyone of them. Trust me...Lol! Some fish like to play the field, and if there's other males around then he lets them know it's his field.

 

[MattS99]

More females will probably do the trick. You can pull of a 1 male to 2 female ratio, but I prefer 1 male to 3 females.

 

[Torkelgutt]

I'd rehome him. Find a fish store to trade him into. Or free to good home.

Won't that just be handing the problem over to someone else, though?

More females will probably do the trick. You can pull of a 1 male to 2 female ratio, but I prefer 1 male to 3 females.

Hm, I see. I was under the impression that a 2 to 1 would be more than enough. At least it has been in the past. Might give this a shot.

 

[V227]

Diluting aggression by adding more fish is a common strategy. Matt sounds like he knows a thing or two about guppies. His male to female ratio suggestion seems like a good one.
The game is to provide too many targets for the aggressor to focus on, but not so many as to overstock your tank.

 

[Angellove78]

Some fish work out in different aquarium with different fish is why I suggested. More females might work, only one way to find out. Good luck!

 

[finnipper59]

Some fish work out in different aquarium with different fish is why I suggested. More females might work, only one way to find out. Good luck!

It's very common for schooling fish to develop an alpha male (and female somtimes) role. I had the same problem with 3 male angelfish and 1 female. She paired off with a male, but there were so many fights among the males that she wouldn't spawn and started isolating in a lower corner. I decided to try a different water conditioner with my water changes called AmQuel Ammonia remover since it also said it would remove chlorine and chloramine. But it also said that it removes pheromones that build up in the tank. Since I've been using it, the fighting has stopped and the female is now swimming around the tank peacefully. I not suggesting it would fix your situation, but just wanted to share that it worked for my situation.

 

[Torkelgutt]

Follow-up, in case someone else runs into the same problem:

I kept the aggressive puppy in a breeder box in my main tank for 4 weeks, feeding him when I fed the others but not letting him interact with anyone except through the mesh netting. After letting him back into the community 6 days ago now, he's been behaving perfectly.

I made no changes to the population of the tank, but did reorganize plants and decorations when I did a 40% water change the same day I let him out of the box.

Hopefully this behavior will continue, and hopefully it can help others who might have the same issue and (like me) neither want to re-home or euthanize.