Oh my goodness...you have a pleco in a 3 gallon tank? I have to be frank with you, this is a very bad situation and these tanks are hideously overstocked. Here's some info that I really hope will help:
Tank 1 - 5 Gallon
4 Glofish - min. school size 6 min. tank size 20 long/29 gal
4 Red Eye Tetra - min. school size 6 min. tank size 30 gals
3 Guppy - min. group size 3 min. tank size 10 gals
2 Julii Cory - min. shoal size 4-6 min. tank size 20 gals
2 Black Neon Tetra - min. school size 6 min. tank size 10 gals
2 Gold Barb - min. school size 6 min. tank size 30-40 gals
1 Pleco - Do you know what kind of pleco? Could be anything from 20 gals min. to over 100.
Fish that are suitable for a 5 gallon are one betta or a school of micro rasbora. There isn't much else besides shrimp and snails.
Tank 2 - 3 Gallon
4 Dwarf Gourami - Do they fight? Typically you can only have one per tank. You can have 1 in a 10 gal. If they don't fight at all I guess you could have all four in a 20 gal..29 would probably be better.
6 Neon Tetra - min school size 6 min. tank size 10 gals.
1 Pleco - same as above
Fish that are suitable for a 3 gallon are maybe a school of micro rasbora depending on the dimensions of the tank. Otherwise only shrimp and snails.
You could increase each fish to their proper group size and easily fill a 55 gallon with them. In that case everything would work except for the plecos if they are common's or another large species. Or you could get everything into a 30 gal and a 20 gal. If this isn't an option I would recommend you look into rehoming the fish. I don't want to sound critical, I am not judging you, but the situation the fish are in right now is not fair to them.
Also I wonder if you cycled these tanks? With this type of overstocking I'm guessing there are a lot of toxins in the water poisoning the fish. Do you have the kit to test for ammonia,nitrate, and nitrite?