High
ammonia levels are probably from you adding fish (I noticed your other thread about more fish) I'm not sure which tank you're talking about but you have problems in both tanks....
The 1.66gal you have too many animals in that one tank. Two guppies and then a frog is too much for such a small tank. So that could be the cause of the ammonia.
If it is the 10 gal (which I'm guessing this is the tank you're talking about) you are going to want to get rid of your pleco those fish produce ALOT of waste and they also get VERY large. So your pleco will outgrow the tank in a matter of weeks (if it is not too large already) and he will get stressed and then probably sick and die. You also have quite a few fish in such a small tank. In one of your other posts you mentioned you also have two platy fry in the tank as well and I'm guessing since you said you have two female platy in the tank then I'm guessing you have a male as well which adds even more waste.
I don't reccomend going straight to chemicals to fix your tank. How often do you do water changes? I reccomend doing some daily until you get your levels back to normal.