It’s not because we can eat something that we should. For example, you can eat hot dogs. But eating only hot dogs every day would certainly be bad for you, and could lead to obesity, malnutrition, and death. The same goes for frog tadpoles when it comes to fish food.
Tadpoles should not be fed fish food due to the lack of calcium, nutrients, and minerals required for successful tadpole development. Solely feeding tadpoles fish flakes, pellets, or wafers can lead to malnutrition, stunted growth, increased cannibalism, and death.
Frog tadpoles should be fed a healthy balanced diet when kept in captivity. Let’s have a look at why tadpoles should not be fed fish food, as well as what you should feed captive tadpoles, and appropriate dosages.
Why Fish Food is Unhealthy for Tadpoles
Fish flakes, sticks, pellets, and wafers commonly contain animal-based meals, vitamins, and fillers that are not adapted to tadpole nutritional needs. Feeding tadpoles a diet solely based on fish food can lead to malnutrition, stunted growth, increased cannibalism, or death.
Fish food often contains animal-based meals (shrimp, squid, fish, oyster shell), spirulina, worms, and crustaceans, as well vitamins and minerals including riboflavin, niacin, biotin, zinc, riboflavin, manganese, vitamin E, C, and B.
These may seem great for tadpoles! However, frog tadpoles are herbivores until they develop legs. Tadpoles also require calcium in their diet, which is often lacking in common fish foods.
Worse than that, fish food often also contains a wide variety of fillers and preservatives such as husk, sorbitol, yeast, salt, sugar, lecithin, potato protein, pigments, colorants, soybean grits, wheat flour, maize bran, rice polish, wheat bran, and preservatives.
High-sodium, high-sugar, and low-nutrition ingredients can lead to malnutrition, dehydration, and death in tadpoles. Tadpoles should not be fed foods with low nutritional value.
Fish food may also contain products that are bad for the environment such as palmitate derived from palm oil which is a product that stems from the destruction of the rainforest. The destruction of habitat and deforestation for human resources (such as cheap palm oil) is a reason why frogs are going extinct. Feeding frogs products containing such ingredients somewhat defeats the purpose of caring for tadpoles.
One of the most common reasons tadpoles die in development when it comes to food is lack of calcium, or an imbalanced diet leading to malnutrition, increased cannibalism, stunted growth, or death.
Learn more about what tadpoles can eat on our blog
None of these fillers, colorants, or man-made products are healthy for tadpoles. So let’s have a look at what should be fed to tadpoles for healthy development.
What You Should Feed Tadpoles
Before we dive in I just want to reiterate that this is for people caring for captive tadpoles. Do not feed tadpoles in the wild, they can find what they need within their environment.
As a general rule, tadpoles are herbivores from 0 to 6 weeks until they begin to develop legs. At that stage they are omnivores until they become froglets. Once froglets, frogs are obligate carnivores.
Tadpoles that do not yet have legs can be fed a balanced diet of algae, boiled broccoli, cucumber skin, lettuce, leeks, cabbage, watercress, spinach, kale, zucchini, duckweed, phytoplankton, detritus, phytoplankton, hornwort, cryptocoryne, java moss, java fern, moss, and other leafy greens.
These greens should be thoroughly washed before being fed to tadpoles as they could have pesticides, herbicides, and other dangerous chemicals on them. In order to make it easier to feed them to tadpoles, you could boil or freeze these vegetables, and then let them cool before feeding.
Many of the above-mentioned leafy greens contain high amounts of calcium which is needed for successful tadpole development (Lassiter et al., 2020). However, too much oxalate or oxalic acid found in some of these vegetables, notably spinach, has been found to lead to renal tubular necrosis and death (Forzán et al., 2014).
Therefore, just like for humans, a varied and balanced diet is essential for healthy tadpole development. Be sure to feed them one or more different greens (mixed together), and different foods on different days of the week for better chances of successful development.
Once tadpoles begin to develop legs, they should continue to be fed a balanced diet of leafy greens that also includes adapted animal-based foods such as worms, ants, zooplankton, egg yolk, and aphids.
In any case tadpoles should not eat fruits or processed foods. Fruits are often too high in sugar and can be detrimental to tadpoles. Processed foods tend to contain high amounts of sodium which can also be detrimental to tadpoles due to dehydration.
Learn more about what to feed captive tadpoles on our blog
How to Dose Tadpole Food
As a general rule, each captive tadpole should be fed ¼ teaspoon of food at the “young tadpole” stage, and ½ teaspoon of food once they begin to develop legs 1x per day. Adjust how much food they need based on how many tadpoles you have.
Here is a general idea of how much tadpoles captive should be fed:
|Number of Tadpoles||Tadpole Age||Amount of Food|
|1||0 – 6 Weeks||¼ Teaspoon|
|50||0 – 6 Weeks||¼ Cup|
|100||0 – 6 Weeks||½ Cup|
|200||0 – 6 Weeks||1 Cup|
|1||6 Weeks – Froglet||½ Teaspoon|
|50||6 Weeks – Froglet||½ Cup|
|100||6 Weeks – Froglet||1 Cup|
|200||6 Weeks – Froglet||2 Cups|
Be sure not to dump the food into their environment and take your time slowly adding it in over a 30 minute period or until they stop eating. Adjust feeding quantities to more or less depending on how much your tadpoles consume over a 30 minute period (CTNF).
Everything should be eaten after 20 to 30 minutes. If they are still hungry, feel free to feed them a bit more but slowly to see what their ideal needs are. If there is food leftover and the tadpoles are done feeding, take it out so it does not rot and degrade the water quality.
See our complete guide on how to feed tadpoles on our blog
Lassiter E, Garcés O, Higgins K, et al. Spindly leg syndrome in Atelopus varius is linked to environmental calcium and phosphate availability. PLoS One. 2020;15(6):e0235285. Published 2020 Jun 29. doi:10.1371/journal.pone.0235285
Forzán MJ, Ferguson LV, Smith TG. Calcium Oxalate, Nephrolithiasis and Tubular Necrosis in Recent Metamorphs of Rana sylvatica (Lithobates sylvaticus) Fed Spinach During the Premetamorphic (Tadpole) Stage. Veterinary Pathology. 2015;52(2):384-387. doi:10.1177/0300985814535607, 2014.