Hi,
a great no maintenance and fast growing plant is Water wisteria - - it is in all my tanks and left floating. the frogs love it!

As for the tetras, they will be no challenge for the frogs - - a 3" ACF can eat a 3" goldfish...


and keep an eye on your water quality! Using water from the original tank does absolutely nothing to aid cycling. What kind of filter are you now using, how long has the tank been set up, and how long had your previous tank been set up and what filter were you using then.

It takes about 2-3 months for a beneficial bacteria colony to develop in a filter and is sensitive even to trace amounts of chlorine - always use a tap water conditioner when doing a water change and never run a filter cartridge under the tap to rinse it off, rinse it off in a bucket of dirty tank water to remove any waste. A filter cartridge should only be replaced when it is literally falling apart- maybe once a year. And even then only replace a portion of the cartridge at a time to prevent throwing your tank into a mini-cycle due to a severe loss of your bacteria colony.