Tadpole Weirdness

This past summer, 2007, my kids and I dug a giant mud puddle in our back yard in metro Atlanta. It is about 12 feet long by 4 feet wide with three sections of about 15 inches deep, 2 feet deep and 3 and a half feet deep. We lined it with scraps of vinyl flooring then a blue waterproof paint tarp. We put in approximately six bags of playground sand. We filled it with water and waited about a week. In mid-August we went to a local nursery and bought about six water plants. While at the plant nursery we were given about fifty tadpoles. The facility didn’t sell tadpoles; these had just turned up in their water garden department. We put them in the puddle/pond. A neighbor donated an old air pump for an aquarium. We bought three air stones and ran an air line to each section of the tiny pond. I bought some cheap flake fish food. The tadpoles seemed to like our pondlet a great deal.
In September my husband brought home three crawdads from north Georgia. I fished two back out of the pond and commanded him to take them away. The third we have not seen in months; maybe he is dead, maybe he has run away.
My eight year old son skims the leaves and pine straw from the surface of the little pond everyday. He has loved watching the tadpoles. We have remarkably little algae and the water is clear enough that we can see the bottom in each of the two shallower sections. The tadpoles’ numbers have been dropping steadily despite the fact that we have seen them eating tiny things from the surface of the water, eating the water plants, and occasionally eating the flake fish food that settled on the bottom of the giant puddle. The remaining tadpoles kept growing bigger and fatter.
It is now November 2007. We’ve had the tadpoles at least three, possibly four months, but still there are no frogs or toads. Worse, their may be something wrong with the tadpoles or something killing the remaining tadpoles. My son called me out to look at the tadpoles on Monday November 12. Two were laying tummy up looking quite dead. You could barely make out the tiny rear leg nubs. They seemed very immature to me considering how long we’ve had them. Stranger still, about four are floating in exceptionally shallow areas near the edge of the pond and they are encased in some sort of white jelly substance. The encased ones are lying tummy down. I thought my eyes might be playing tricks on me so I gently touched one and it is definitely a jell type substance and is somewhat firm to the touch. I am not even sure if these tadpoles are dead; perhaps they aren’t.
Googling has rendered nothing but countless articles about the jell that frog and toad eggs are laid in. I can find no mention of a jell encasing tadpoles that really ought to be turning into frogs or toads by now.
So, are these tadpoles dead or alive? Is this jell some sort of strange tadpole cocoon? Is the gel a disease? A fungus? What is going on with our tadpoles and should we do something; intervene in some way?
Thank-you,
Terri

You have a nice do-it-yourself inexpensive pond! If you're serious about pond keeping though, I suggest replacing the paint tarp with an EPDM liner. Some tarps leach chemicals (which could harm the tadpoles) while others tear easily and/or don't last long. Otherwise, your pond sounds pretty nice.

First, we need to determine what species of tadpole that you have. Bullfrogs take two full years from the time they hatch to when they turn into adults. Green frogs take a full year. Most tree frogs and toads only take two to three months. I would guess you have bullfrog tadpoles, especially if they are over 1.5 inches long. How big are they? If some have leg nubs, they are nearing metamorphosis. That is a dangerous time for them and many die at that time. It's not uncommon to find them dead at that point. You can expect that only a few per hundred eggs that are laid will make it to that point and maybe a third of those turn into adults.

The slime you're seeing could be a few things. It could be simply the skin sloughing off the tadpoles. That would mean they are deceased or nearly so. If you pick them up, and they don't move, they're most likely dead. They could have died from the stress of metamorphosis, lack of oxygen, water quality issues such as high ammonia, fungal infections, or other things. Tadpoles also are attacked by fungus quite often. That will cause them to have a white film sometimes. Since most fungal medications are also harmful to the tadpoles, they won't do too much good. There are a few though that should be safe - pond salt (at 0.05% concentration) and PimaFix by Aquarium Pharmaceuticals (an all natural antifungal). I suggest adding those to the pond. Pick up any slimy or unside down tadpoles (you may want to wear gloves if you're grossed out) to see if they move. If you get no response, they're most likely gone. What is the water temperature? If it's over 50 degrees F, the tadpoles will respond to being fondled.

The pond has some aeration but no filtration? Filtration and also water changes (with added dechlorinator) can really help improve the water quality which in turns makes it less likely that the tadpoles would die. I also suggest testing the water's pH, hardness, ammonia, and nitrite.

If you read up on pond keeping, it can seem overwhelming because there's so much information. I'm still learning but that's what's so exciting! I hope you can improve your pond and enjoy tadpoles (and their resultant frogs) for years to come!