Can you post a picture of the pleco?
If your gouramis are both brightly colored, they are males. The females are drab in color, sort of silvery with faint colors. They're not commonly found for two main reasons: 1. they don't sell like the males because of their color, or lack thereof, and 2. breeders like to keep them so they can breed them to death.
If you have two male gouramis and you add a female, one of the males will most likely have to go. However, adding another male, for a total of three, will probably work as they'll spread the aggression around and no one gourami will get the brunt of war. Dwarf gouramis aren't as hardy as they used to be 20 years ago; they seem to kick the bucket rather easily these days. They are also very susceptible to a virus where they are bred in the far east. I can't recall the name at the moment.
A temperature of 79° works fine for most fishes, especially captive-bred species. Wild-caught, however, that's a different story. Exacting temps for most fish are not normally required, unless you're trying to breed a wild-caught fish, and even then there's some wiggle room. Most captive bred fishes these days are generations away from their ancestral waters so they've adapted accordingly.
Neons do best in 73° to 77°. Another fish that looks very similar, the cardinal tetra, will do better in 77° to 83°. Rams and cardinals compliment each other very well. Have you noticed how many ram/cardinal pictures are floating (pun intended) around? A lot. That's because they both thrive in the same kind of water: warm water. Rams have even been collected in water as warm as 88°! There are no overhanging trees to block the sun where they are found. Discus' will also do well in warm water, but they're not for a 29g.
Some cold water fish for a 29g: white clouds, bloodfins, pearl Danios, peppered cories, zebra Danios, paradise fish, Florida flagfish, mosquito fish, guppies, platies, goldfish, ets...
Warm water fish for a 29g: bettas, angelfish (just 1), C. sterbai, cardinals, chocolate gouramis, hatchetfish, gold nugget pleco, etc. The clown loach you were thinking about also does very well in warm water, but they're not good for a 29g, unfortunately.
The aforementioned list is in no way exhaustive; it's just what came to mind as I typed. As I said earlier, though, most fish will do well in your set temperature, even the fish I've differentiated. Doing well and thriving are two different conditions, though.
All that said, please keep in mind that there are no absolutes to anything I've written, as fish don't read what they're supposed to be like. Every now and then I get shocked when I read a report about a fish doing something they've never been known to do. We know not nearly enough about them...
David
i dont want to disrupt the peace in my aquarium
