Last Updated: 11/12/13
Why Did My Fish Die After The Toads Laid Eggs?
Setting up a Toad Nursery
Will My Pond Be Overrun With Toads?
Sometimes after toads lay eggs in a pond, fish die. There are a number of theories as to why this is. The higher the concentration of eggs to pond volume in the pond, the more likely this would happen. While American and common toad eggs are mildly toxic, most fish know not to eat them. They may taste a few but they taste bad, and the fish gets sick. It rarely dies and learns not to eat the eggs ever again. Occasionally you may get a "stupid" fish who eats the eggs or toad tadpoles (who also are slightly poisonous and taste bad) anyway and dies. Certain other species of toad are more toxic, such as the Marine Toad. If a fish test tastes one of their eggs, it may die straight away. I am not familiar with species other than the American or common toad so I cannot comment on these other species.
The most likely scenario as to why American toad eggs kill fish is this. Toads are very prolific breeders. A single female with a few suitors can add many thousands of eggs and a high concentration of excess semen to the water. Both of these add wastes to the water just as fish waste would. Of course, while courting in the water, the toads also excrete wastes as well. This all increases the ammonia concentration in the pond. In small ponds, this may be too much load for the biological filter. All the excess organic material in the pond can also drastically reduce the dissolved oxygen content in a small pond. Large ponds (over 1000 gallons) are largely unaffected by a few breeding pairs of toads. Thus, in a small pond following a toad spawning, fish may die from lack of dissolved oxygen and/or ammonia poisoning.
Before the toads get in the water, the pond could be netted to keep them out. But, once they are in there and have laid eggs, you can do the following to reduce death of aquatic animals.
1. Increase surface agitation and aeration of the water to increase the dissolved oxygen content.
An air stone works well for that if the waterfall, fountain, spitter, etc. is not strong enough.
2. Net out or otherwise remove most of the eggs and move them to a natural pond nearby or a smaller pond like a kiddie pool.
3. If possible, do a 20 to 50% water change in a small pond (under 1000 gallons) following a large toad spawning.
4. Keep the filters especially clean.
5. Add activated carbon in a mesh bag to the filter.
5. Add liquid or dried bacteria meant to improve the nitrogen cycle can also help.
I removed excess toad eggs and tadpoles from some of my ponds and put them in my other ponds. They can also be moved to local natural bodies of water. Toad eggs and tadpoles transplant well. I think it is much better to relocate them than kill them as many suggest. Adult toads are great insect eaters and pose little bother to anyone (except those people who cannot sleep through the males' trills). Toad killers suggest killing by tossing tadpoles on the lawn to dessicate, poisoning with fungal killers (adding chemicals to a pond should not be done haphazardly), or even mowing over the newly formed toads! Please, just move them to another site. All my ponds used to have toad tadpoles in the spring, and nothing bad has happened (since 1997).
If you want to remove excess toad eggs and toad tadpoles but do not want to kill them, you can set up a toad nursery. All you need is a shallow, fish-safe container. A kiddie pool or plastic storage box works well as does another pond just for amphibians. Fill the toad pool with toadpoles or eggs. Use water from the main pond or water aged outdoors. Toss in some live plants such as anacharis, algae-covered rocks from the main pond, and assorted pond life. Place the toad pool in an area with partial shade so they do not overheat. Put in a ramp of some sort for them to get out. It can be a log or even a pool toy. The addition of mosquito dunks or liquid (see the section on mosquitoes for more information) will keep mosquitoes from hatching out of the water. If you set up a toad pond before breeding begins, the toads and frogs will find it on their own. They should prefer it over a pond with fish that may eat their offspring. In areas where ponds freeze, toads will leave the water before fall. If there are frog tadpoles (bullfrogs, green frogs, etc.) still in the pond in the fall, they will need to be moved to a body of water that will not freeze solid.
When the toad tadpoles first hatch, they are very tiny, flat, move very little, lay on the bottom,
and do not look anything like tadpoles. They can be raised in a small pond (tub pond or kiddie
pool which works well). A small air stone can be used to help keep it oxygenated but do not use
a pump or filter because it will suck them in (my filter pads get covered in tadpoles). After
almost a week, the toad tadpoles will begin to swim around. They will eat algae and fish food.
They may or may not eat hair algae but will eat other algae. You can feed fish food to the
tadpoles to supplement their diet of algae if there is not enough. I fed tadpoles Cheerios, koi
kookies (sold at many pond places including That Pet Place, Drs. Foster and Smith, and
AquaMart, go here for contact information); yes, it is spelled
kookie and not cookie; by 2007 it seems they do not make them anymore), goldfish flake food,
pond floating pellet food, and algae tablets made for plecostomus catfish. Here are some foods
you might feed toad (or frog) tadpoles.
Drs. Foster & Smith deleted their affiliate program so these links will no longer work. I am leaving up the pictures which are still working for now.
When I put in Cheerios, they all hitched on and spun it around like an amusement park ride. When I put in koi kookies, the kookie got covered in a black mass shortly. Change about a third of the water every week. This may be hard if there are a lot of tadpoles and little water. You can either run the water to be changed through a net to catch the tadpoles, toss the changed water with tadpoles into another pond (I do that since I have so many ponds), or discard some (to reduce their numbers). Sometimes, I just do not change the water since there are too many tadpoles, and they survive. After a few months, the tadpoles grow legs and spend time on wet vegetation when they get legs but still have tails. It is important that they have places to do this. Lotus and lily leaves work great as do very shallow areas of the pond. After they absorb their tail, the tiny (1/3 inch or so) toads leave the pond in search of bugs to eat. They have to have a means to get out of the water as they can only jump about a few inches high at this time. In a few months, they have grown to a little over half an inch. From every spawning of toads of thousands of eggs, only have a few make it to adulthood which is fine because you do not want to be overrun! Many will starve, get eaten by each other or any animals that get to them, die from ammonia, nitrite, and/or organic build up from overcrowding, get mowed or run over, or get squished.
See also - amphibian ponds.
Some ponders are concerned that their yards will become over run with toads but this does not happen. Many eggs fail to hatch due to fungus, poor water quality, or infertility. Of the thousands of toad tadpoles (I call them toadpoles which is scientifically incorrect but cute) that do hatch, many will be eaten by other toadpoles and perhaps some animals that are more tolerant of their distaste. Even the most algae-ridden pond usually cannot feed so many toadpoles so they run out of food. Many starve, and many others eat their siblings. Toadpoles only eat surface algae and debris and will not usually touch suspended algae or string algae. They congregate in the warm shallows when the sun is out. After a few months, they vanish overnight. Their legs grow seemingly overnight, and they leave in the dark. Of those toads that make it to land, many are eaten by birds and other predators. Some are squashed by cars. Many freeze to death over winter or starve. So, from say 3000 eggs laid in your pond, maybe if they are lucky, 10 will return to the pond in a few years to breed themselves. Then, there are quite a few wrestling matches. In my pond in 1999, there were about 12 males but only a few females whereas two years before when the pond was new, only a single pair found it. Perhaps most toadpoles are born male, or the females found a better pond than mine!
Adult toads will only eat live animals. They can eat whatever moves and fits in their mouth. Adults love crickets, mealworms (all three species, see my mealworm page), earthworms, beetles, slugs, and well anything small that moves! Toadlets (tiny newly-morphed toads) will eat pinheads (newborn crickets), wingless fruitflies, and blackworms (semi-aquatic) which can be bought from most aquarium stores. You can also raise mealworms and feed the baby mealworms to toadlets. In the wild, they again eat anything small that moves from beetles to ants to worms to thousands of species of baby or small insect.
For some reason, I got about six questions on feeding baby toads in June of 2004 so I thought I needed to add that to my site but it was already here! I guess no one reads around!
Also, see my section on feeding frogs and toads.
Wind & Weather sells neat things for your garden!
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See the master index for the amphibian pages.
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