Originally Posted by Mark Hewitt
Thanks for that. I was torn between mollies and platies anyway, you think they are the way to go then? Would keeping male platies present any issues with regards to agression etc?
I did have a shoal of 3 guppies, but sadly, they all died
From my experience both platy and guppy are peaceful community species. There is always the chance for a psycho fish of any species, just like you'll hear stories about peaceful dwarf puffers and male bettas in community tanks. There's no guarantees in fish keeping.
With that said typically aggression is due to fish species, line of sight (LOS) issues, and stocking level. Understocked tanks rarely have bad aggression problems, as do heavily planted/decorated tanks. The real problems are when you have a relatively bare tank and are overstocked somewhat (typically how all beginners start out and why we get tons of, "my fish are being attacked!" posts).
Severely overstocked barren tanks actually have an opposite effect usually. The fish are under so much stress and there is no way to easily claim a territory that they normally play nice (but are much more prone to disease from the stress). This is why aquarium shops can have extremely overstocked tanks (filtration aside) with seemingly little aggression.
Anyways, I would get single variants of platy to brighten up the colors in the tank that will work well with your current stocking. In my tank I have a blue platy type that has orange around the body which overall has a very dark presence, and a beautiful silver/red/polka dot type that stands out against my plants well. There's probably a near unlimited variety of types out there between shops and private breeders (I was given these by a friend from his personal pond that has thousands so I doubt the ones I have fall into a specific brand name). That is one of the cool things when breeding; you never know what offspring will look like. Most times they are similar to the parents but every so often you get a recessive gene or mutation that has them completely different.