I need a bit of advice

[k13k07]

I have 3 angels in a 30 gallon tank with a couple tetras and bottom feeders. (Eventually I'm planning to upgrade.) And my biggest one, Loki, I'm afraid is a guy, because he's started picking on my second angel, bubbles. (I got them at the same time, they have similar markings, they used to always be swimming together, and I'm fairly sure they're probably siblings). Sometimes I see Loki running into bubbles, and he just swims down or hides from Loki when he sees him swimming towards him. I've also seen my third angel, Spot, copying Loki.
Is there anything I can do to stop Loki from being a bully or is it just that he's maturing and sees Bubbles as competition?
I have thought about a divider for right now, because I don't have room to set up another tank I'm hoping I won't have to give any of them away
This is Loki
Bubbles is at the top, Spot is on the right and Loki is at the bottom

 

[ryansmith83]

They are probably coming into sexual maturity. Your best bet is a larger tank. Also, keeping them in larger groups sometimes helps spread the aggression out a bit. If two of those pair off, they are going to constantly give the third one hell to the point that it'll be stressed, and maybe even injured if it has nowhere to go.

 

[k13k07]

Thankfully my 30 is rectangular so they usually stay on opposite sides - that is until spot goes to the other side (seems oblivious lol) and loki follows, chasing bubbles to the opposite side. I haven't seen Spot get picked on at all, leaving me to believe maybe loki thinks that spot is a female
Here's a better pic of spot. Unlike the other two, there isn't a slight bump on the front of the head between the mouth and fin.
What size do you think would be good to keep them apart? My current tank was given to me, it measures about L-36in W-11.5in H-16in. Don't know if I have the room to upgrade right now (brother and I live on the third floor of an old building and are looking to move), but I have to do something if I can. That's why I was thinking of a divider, but I don't want to keep the rest of them on different sides