I plugged in all your credentials into aqadvisor and this is what I got:
Suggestion: If you want to keep more than 1 Platy, minimum recommend male to female ratio is 1:2 (M:F). You will be less likely to experience problem if you get even more females.
Note: Common Pleco needs driftwood.
Warning: Common Pleco is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 18 inches.
Warning: Common Pleco requires a tank with more height.
Note: African Dwarf Frog are 100% aquatic & should never be out of water. They may jump - lids are recommended. Do not feed freeze-dried or dry pelleted foods which can cause intestinal blockage and death. They are meat eaters and they wont eat flakes. They will eat any fish that will fit in their mouths. Hand feeding recommended if kept in community tanks. Tank depth should not exceed 15 inches because they come up for air and any deeper can be difficult.
Warning: Your selected species may eventually require 672% of your aquarium space. You may need to deal with territorial aggressions later on. Try removing some of (Pterygoplichthys pardalis, Hymenochirus boettgeri) or get a larger tank.
Recommended temperature range: 23 - 25 C. [Display in Farenheit]
Recommended pH range: 7 - 7.5.
Recommended hardness range: 11 - 15 dH.
Warning: You NEED to add more aquarium filtration capacity!!!
Your aquarium filtration capacity for above selected species is 25%.
Your tank is too small - it will require massive amount of frequent water changes each week!
Your aquarium stocking level is 298%.
Your tank is seriously overstocked. Unless this setup is temporary, you should consider a larger tank.