Thanks Andy, I only keep central & South American fish right now, mostly livebearers. The fry are in a tank by themselves & I do use city water, but all my tanks have it, so that would not explain why they are growing slower that the others. I was assuming the swordtails would grow as fast as the platies, since they are so closely realted. I don't remember how fast the red & greens I raised in the past grew, I just wasn't keeping track of it back then.The PH is slightly alkaline, about 7.2. I started thier 20 gallon tank with water from the tank the parents are in, I change 20% once a week with tapwater treated with Startright & left to sit 24 hours. I don't want to alter the local water much, because after I sell them, that's what they will likely be in. I've used blackwater extract and peat in filters for angelfish, but the swordtails shouldn't need it from everthing I've read.

EDIT; I havn't checked the hardness, I'll get a kit soon & check that, but I am not having a problemm with my other fish. The parents & platies seem very robust & happy.

****Raises hand to take Oath*****

I do solomenly swear never to mention fish while Jill is in the wet spot!!!

The peat acidifies the water gradually. Switch to bottled water! The mineral content and "acceptable" levels of phosphate can hamper proper growth. Also the food you may be feeding them might not be helping either. Use liquid "Livebearer Fry" food to feed them. Marine Depot has it online!

I strted them on Liquifry & scraped algae from the parents tank, it was full of rotifers & they loved them. They ate finely crushed flakes right away & have also had fruit fly larva & fruit flies. My neons are doing great in my water, that's why I doubt that's the problem, they would be more picky about PH & hardness than live bearers wouldn't they? I think I'll try putting the next brood in the tank the platies are in, since they are doing so well, putting the female platies in my community tank & giving away the male. I'm running out of room.I'll let you know how that goes.

I guess I could try spring water from a local spring,in Maryland I had a rain barrel, but here it would be frozen half the year.I can't afford to buy bottled water, I have 6 tanks going.

Ah, A true devotee to the world aquatic! PH is very important but so is mineral content as well. The stuff in California tap water would raise many an eyebrow if people tested it. I did. the tap water here is 26 to 30 degrees (german) mineral hardness. You could beat people to death with that water!

So true

Mirror do you like aquariums?