Guppy Bullying

So, I am taking care of my friend’s male guppy while she is on vacation, and he is in a 2.3 gallon tank. She used to have two males, but a couple months ago one of them died and now she only has one(Mangrove). For her birthday I got her another guppy, (she knows and was okay with it) and I just finished quarantining him. He is a little smaller then mangrove, but he seems pretty healthy. I acclimated him to the water and then put him into the tank with mangrove. Now mangrove is chasing him all over the tank and lunging at him, but never actually biting him. Should I be worried or will mangrove calm down?

Sometimes the new guppy turns around and swims toward mangrove, and then mangrove looks surprised and backs up, but mostly mangrove is chasing the new guppy.

 

A two gallon tank is too small for two guppies, but to address your concern, do you know the two genders of the guppies?

If they're two males, that is aggression. If they're one male and one female, the male is probably trying to mate, but the ratio is all off.

Try to send a picture off the two.

 

I know that a two gallon is too small, I am taking care of them for my friend, and that is what she has. They are both males, I already said that. I know it is aggression, I am just wondering if it is mangrove establishing his dominance and if he will eventually stop.

 

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In my experience with all-male guppy stockings, especially in smaller tanks and with less fish, aggressive guppies don't relent.

Is Mangrove approaching his tankmate from below, with his ventral fins flicked forward at the belly of the other guppy? If so, this is just ordinary mating behaviour. But, if he really is just chasing at the other fish, and the newer guppy seems stressed or hides from the aggressor, I would return the new fish and attempt to find one with a more docile personality.

In this situation, even with a larger tank, I've tried rearranging the decor, isolating fish, adding more live plants to break up lines of sight, and just waiting for it to blow over. The aggression never let up. In the end, I simply returned the aggressor, and replaced him with a new male guppy who was, luckily, much more tolerating and this solved the aggression problem.

But, aside, I hope that you will be able to figure out what's going on with Mangrove and find something that works for your tank right now! (even though the tank size is really not ideal for guppies).

 

It was from below, so I guess he was trying to mate with him, but mangrove has stopped now.

As I said before, if I could change the tank size I would, but they are my friend’s fish, and she won’t get a bigger tank.

Thank you to both of you for your input!

 

Just add one or two grains of aquarium salt to your tank and see if it changes things, sometimes stress for unknown reasons can cause the fish to chase each other. Aquarium salt brings down the stress levels big time

 

I think they just needed some time to settle in. They get along fine now