Guppie Terrorizing Other Tank Mates. How To Fix?

[watertown28]

I noticed some fin loss on some of my Neons in the tank

The stock WAS:
5 Neons
4 Emporer Tetras
2 Guppies

30 gallon tank

Now I added 3 neons earlier this week. They were all in perfect shape.
Then I noticed some loss on the fins on a few of them and was wondering what was going on. I sat and watched and found out who it was. It was one of the guppies who was literally chasing them around ( one in particular ) and nipping the fins.

Needless to say, the one that the guppie was hard up on perished last night. Now hes working on the other ones. He does not seem to be much interested in the Emperors for some reason...mostly because I think they fight back...

So, I need to correct this problem and do it fast. Neons are touchy.

Here are the options:
72 gallon. I have 8 Dinoes ( mix longfin and zerbra ), 2 Emerald Corries, 2 Julii Catfish, 4 Pristella Tetras, and 2 Clown Loach in that tank. I fear if I put him in there that he will work on the corries in there.
55 gallon: 3 White Cloud, 8 Rosbora Het, and 6 Red Phantom Tetra in that one. Now the Rosbora and the Phantoms are extreamly shy fish in that tank for some reason... I am not sure why... then again I dont think they would like a aggressive fish in there either.
10 gallon: 5 Gold Pristella Tetra in that... pretty much stocked for that tank.

Now I do have a strange shaped tank that has to be around 20 gallons and another 55 gallon tank. Both are not set up, nor do I know if they leak or not because I just got them.

So what to do?

 

[Akasha72]

is the tank planted? It sounds territoral behaviour. I'm just thinking that if they have somewhere to hide the guppy might just get bored of harressing. Has he got any females to keep him occupied?

 

[watertown28]

is the tank planted? It sounds territoral behaviour. I'm just thinking that if they have somewhere to hide the guppy might just get bored of harressing. Has he got any females to keep him occupied?

I thought I had a female in with him ( had one of each at least that is what the fish guy told me ) The other seems to be chasing a bit too. Seems to be in one corner of the tank the fish are defending ...

As for the plants, no no plants at least worth hiding in. I May go to walmart and pick some up ( fake ones ) if that is the case.

I was also thinking of moving the neons to the 55 gallon tank if needed... son will be heartbroken though if I need to do that though, he loves those fish.

Edit: I think I figured out the sexes of the guppies... I read where the top fin has no color on females while the males will have color... and so will the males bodies.

The one who is aggressive has no color on top fin and is in fact "white" on the body