I have fake plants in all 5 of my tanks and I want to switch to real plants. I have regular gravel substrate in all of the tanks and don't to go through the expense of changing it. Are there any real plants that will grow in the regular gravel substrate? It's not the big chenky stuff. Also, can I trim the plants so that they don't get out of control and I won't be able to see my guppies? My platies are in the other 55g tank,but will have the same trimming issue. So will my endlers in their 40g tank. Any suggestions on plant types? The other 2 tanks are a nursery tank and a grow out tank.

Floating and rootless plants don't care what substrate you have. I used to keep hornwort (Ceratophyllum demersum) weighted down to look like it was coming out of the substrate when really it didn't have roots and got all of its nutrients from the water column. What I did was make a rectangle of PVC tube, bury the bottom half of the rectangle, and wrap the Ceratophyllum demersum around the exposed part. Because the bottom half was buried, it was secure enough to weight the plant down.

I'm not sure if this link works, but if it doesn't you can see an image of that setup in my profile. Photo of the tank: http://www.ratemyfishtank.com/photo-main.php/34771

The one issue is that hornwort grows really fast. That's why I replaced my gravel with kitty litter (100% ground baked clay) and the hornwort with Myriophyllum pinnatum. It grows a lot slower, so I don't have to trim it as often. But it took me about a year to get sick of the hornwort, so I think it would be a good stepping stone for you.

There are also plants like java fern, which roots itself to driftwood. You tie the plant on and it will over the course of a month or so root itself to the wood. Java fern has an intermediate growth rate. It's slower than hornwort but faster than something like an anubias. Anubias would work for you because they're substrate-free, but I don't like that they're basically ungrowing underwater. I had anubias for two years that grew like maybe a dozen new leaves over that entire time period. Slowest growing plant in my experience. And the slower a plant grows, the less harmful nitrogen it removes from your water column. I doubt the anubias helped clean my tank at all.

There are also things like mosses and liverworts. They don't have roots, so they wouldn't care if you have pea gravel. Some of them can be quite pretty, too. I like the look of singapore moss, and I have some in my 10 gallon guppy tank. Here are two pictures:
http://img.photobucket.com/albums/v415/ ... pytank.jpg
http://img.photobucket.com/albums/v415/ ... dangle.jpg
I've got bolbitis, java fern, singapore moss, and Hygrophila difformis in the tank, and my substrate is kitty litter. I like kitty litter because it acts like gravel (it's little pellets) and it costs $3 for 25 pounds of 'Special Kitty' brand.

In summation: If you're going with gravel, you have to choose a plant that gets its nutrients from the water column, not the substrate. These include hornwort (ceratophyllum demersum), java fern, bolbitis, anubias, and other things like water lettuce, duckweed, the mosses, riccia fluitans, etc.

Thanks for your help. Replacing the gravel in all of my tanks plus buying the plants is expensive. That's why I'm trying to find plants that will grow in regular gravel substrate.

If I was you. I would change one aquarium at a time. This way it does not seem to cost as much. Petco has Eco-Complete on sale on there web page. I use this stuff for all my 15 aquariums.