Okay, HEEEEERE'S THE EXPERT!!!!!
I have successfully raised two green frogs from tadpoles that I found in a feeder fish tank, and am raising another one--probably a bullfrog tadpole (if you post a picture, I can identify your tadpole for you! Bear in mind that different kinds of frogs often have slightly different requirements, so it's good to know what you've got ahead of time!).
I kept them in a tank with the water at least 3 or 4 inches deep with gravel substrate piled up at one end so that they could get out of the water if need be. The water was aerated and filtered, and I did weekly water changes along with my fish aquariums--tadpoles tend to be very dirty. They grew fast on a diet of algae tablets, and soon began to spend more and more time above water. When they were fully morphed, I replaced the gravel with river pebbles because frogs, not being the most intelligent creatures, are apt to swallow gravel along with their prey which can cause gut impaction and death. I fed them crickets--starting with little ones, switching to bigger ones as they grew. Unfortunately, they will no longer accept anything BUT crickets...
One frog died due to chlorine poisoning while being kept at a school a while back
(I loved that froggy!) but the other one is still alive and healthy. He is fed one or two large crickets every night. The crickets are fed with "gut load"--calcium and vitamin fortified cricket food that will practically make the cricket a walking multi-vitamin. It is also very important that the frog gets enough calcium to keep his bones strong.
The tadpole I am currently raising is, I suspect, a bullfrog tadpole--which means that once he is full grown, I will not be able to keep him with my Green frog or else the green frog will get eaten.
This tadpole I am keeping in my fish aquarium which has warmer water than the green frog tank in which he was previously kept. Because he is a bullfrog, he's growing a bit slower than the green frogs did, but the warmer water should encourage him to grow faster. Presently, he is four-inch monstrosity with tiny hind legs and arm buds, but, despite his appearance, he is actually a shy, docile algae-eater. I drop an algae tablet in his favorite hiding spot every night, and the catfish clean up whatever he doesn't eat. When he has morphed a bit further--gets arms as well as legs, tail shortens, and a mouth begins to grow, I will put him in his own tank where he will have better access to land and will not be in danger of getting eaten by the green frog while he's still just a froglet.
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NOTE: In feeding algae tablets, I recommend that you use Hikari brand tablets. On the ingredient statement, you will notice that spirulina algae is not the first ingredient--this is because Hikari uses more than just algae in order to make a more balanced formula. So using Hikari will probably be healthier for your tadpole.
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NOTE: Once your tadpole has fully morphed, you cannot return it to the wild because #1, it will be too domesticated and dependent from living in a glass box and being fed and #2, it's illegal--frogs in captivity may pick up and carry diseases that may be detrimental to the wild populations.
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NOTE: One thing I've noticed with my tadpoles is that they often have a tendency to appear dead. I mean, really, dead. You will not believe how many times I've prodded my tadpoles because I thought they had died... and then, to make matters worse, they don't always move at first even when you prod them. So you prod them again, and they nearly give you a heart attack by suddenly thrashing around and zipping away at the speed of light.
So just to warn you: if it looks dead, don't worry, it probably isn't
Please PM if you have any frog/tadpole questions--if I do not know the answer, then I will find it for you.
/web.ukonline.co.uk/conker/pond-dip/tadpoles.htm
