Not a lot of hope here.
1) 10 gallons is too small for a grow out tank for Yoyo Loaches. Good to treat really young ones as a quarantine tank, treat for intestinal parasites and skinny disease, then move them up to a 20 long (30" long tank) for growing out.
2) 10 gallon is great for EITHER a Betta OR a small Gourami (Dwarf, Honey) but not both. These two species are both top of the tank territorial and are highly likely to fight. Pick one, then get some lower tank fish such as a group of small barbs or rasboras or tetras. About 5 of something that gets an inch to 1.5", or more if they are smaller fish, such as Dwarf Rasboras, Ember Tetras, and similar sized fish. Plants that stay a bit smaller are better in a 10, so dwarf things like Wendelove Java Fern, Nano Anubias and similar plants are better than the large growing ones.
3) The Oscar will shred and destroy plants. Try it, but I would not hold out much hope. Get rid of the Oscar, and the other fish are better with plants:
Yoyo Loaches, Firemouths, a school of Rainbow Fish or Congo Tetras and a small Pleco (Bristlenose perhaps) would make a really nice large tank, and these are generally better with plants.
4) Lighting for plants: Anything that looks dim to us will probably not grow anything. Lighting that looks bright to us may not have the proper wavelengths for growing plants, but is a better idea than the deliberate choice of dim lighting. Aim for about 2 watts per gallon using T-12 or T-8 bulbs in the color ranges called 'Daylight', 'cool white', or 'Plant' bulbs. A combination is best. So, over the 100 gallon tank, set up about 200 watts of light. You might get by with a bit less, 100 gallon tanks are large enough that a bit less than 2 wpg seems enough for low light plants.
Over the 10 gallon tank you need even more than 2 watts per gallon just to call it low light. Aim for about 3 watts of the lighting described above, or look into the much better t-5 set ups. If you can get about 15-20 watts of T-5 lighting over the 10 gallon there will be plenty of light for the plants.
5) Fertilizer for plants: Plants need carbon. Some set ups have enough carbon (CO2) from the fish, but many do not. Adding carbon using Excel is a good way in a low tech set up. Other fertilizers can come from fish food. If the nitrate stays up, even with the plants in the tank, then you may not have to add additional fertilizers. If the plants are thriving so well they are keeping the nitrate bottomed out, then they are probably lacking for other fertilizers, too.
38 tanks, 2 ponds over 4000 liters of water to keep clean and fresh.
Happy fish keeping!
