Are tomatoes toxic to fish?

[Jason Yahner]

Half of a tomatoes was found floating in our tank. Could this be a cause for our fish dying off over the last two days?

[randy proctor]

I did the electrical myself, the pump is the same pump in all the tanks,  they are all doing the same pressure, beds are cycling, the heater is a true temp titanium heating system professional series.   They are also in other tanks.    They were all about the same age,  hybrids and the white nile, about 15 of each when the whites began to die, again I moved the white to another tank, thinking it could have to do with different species of them diying..  We had put them together to see which ones would grow the quickest.  White niles hands down in grown. Again the white nile has not been a problem since.  as for the electrical.....I have had my hands in the tank several times lately.  I haven't noticed any curling of my hair.haha  We got the tanks from the same place, made sure of scrubbing them out and even hot pressure washered them.   This all started happening about 1 month ago, noticing the whites dying, and the tomatoes growth to to 6-8 feet tall and very bushy.  Also have put on a tremendous amount of fruit.  Don't know.......thanks for your help, always there for you if you needs answers as well.  Randy & Marie

TCLynx said:

As Jon said, metals or some other contamination from either system components or the source water itself are what I start to suspect on unexplained things that happen several months into a system operation when water quality parameter seem fine and it can't be traced to a DO problem.  Sometimes some sort of electrical fault from a pump or a heater can also be a cause of problems but I think noticing fish swimming funny with electrical problems.

Might be time for a lab water analysis for heavy metals.

[TCLynx]

Sigh, I had problems without obvious answers randy.  Wish I knew what could help you.

[Local Roots Aquaponics]

Randy is the growth of your plants so large that there is perhaps a layer of dead leaves etc rotting on top of your media you aren't seeing? I suspect a mass of rotting tomato leaves could be enough to contaminate the water.

[Liz & Dan]

I know this is an older post, but I just wanted to chime in here about tomato plants and how they have an overly bad wrap about being poisonous!  While I wouldn't suggest eating the leaves of tomato plants in mass quantity say in a large raw salad bowl full, there is not any good science behind a few leaves being toxic. I would certainly look for another culprit for fish die off.  My grandmother always insisted the seeds were poisonous, so at a young age I realized there was a lot of hype around the dangers of tomatos but mostly it's anecdotal not science based. I've been adding tomato leaves to my tomato sauces to enhance the tomato'y flavor since reading this article:

http://www.nytimes.com/2009/07/29/dining/29curi.html?pagewanted=all...

"Accused, Yes, but Probably Not a Killer"

By HAROLD McGEE

Published: July 28, 2009

Here is an excerpt from the article:

There are reasons to be wary of the tomato plant. It belongs to the disreputable nightshade family, whose members accumulate toxic alkaloids. For centuries after the Spanish first took the tomato from Mexico to Europe, fruit and plant alike were considered dangerous. Nowadays the fruit is summer’s star, but the rest of the plant is still suspect.

Unfortunately there’s no authoritative roster of poisonous plants to consult for definitive advice about edibility. TheFood and Drug Administration maintains an online poisonous plant database, but with the disclaimer that it has “no official status” because the information it includes is unconfirmed and constantly changing. So out-of-date and erroneous materials persist. Toxicity is an inexact quality in any case, because it depends on dosage and other variables.

Many handbooks of poisonous plants cite the tomato plant for killing livestock and sickening people. According to the California Poison Control System’s “Poisoning and Drug Overdose,” edited by Kent R. Olson (McGraw-Hill, 2006), the tomato toxin is solanine, one of two alkaloids that make greened potatoes toxic. High doses of solanine kill animals and cause nausea, hallucinations and death in humans.

Sounds pretty damning. But there’s scant evidence for tomato toxicity in the medical and veterinary literature. I found just one medical case, an undocumented reference to children having been made sick by tomato-leaf tea, in a 1974 book on poisonous plants. In contrast to the few anecdotal accounts of livestock poisoning, a controlled study in Israel in 1996 showed no ill effects when cattle ate tomato vines for 42 days.

And it’s a chemical gaffe to attribute tomato toxicity to solanine. Dr. Mendel Friedman of the federal Department of Agriculture, who has studied potato and tomato alkaloids for two decades, wrote in an e-mail message that commercial tomatoes contain tomatine. Solanine, he added, is a potato alkaloid.

There are significant quantities of tomatine in green tomato fruits, which people have long eaten fried and pickled. And tomatine appears to be a relatively benign alkaloid.

In 2000, Dr. Friedman and colleagues reported that when lab animals ingest tomatine, essentially all of it passes through the animal unabsorbed. The alkaloid apparently binds to cholesterol in the digestive system, and the combination is excreted — ridding the body of both alkaloid and cholesterol. The researchers found that both tomatine-rich green tomatoes and purified tomatine lowered the levels of undesirable LDL cholesterol in animals.

Dr. Friedman has also found that an extract of green tomato lowers the incidence of cancer in animals, and last month he reported that both this extract and purified tomatine inhibit the growth of various human cancer cells. Other studies have found that purified tomatine seems to stimulate the immune system in desirable ways.

According to “Toxic Plants of North America” (Iowa State University Press, 2001), by George E. Burrows and Ronald J. Tyrl, a toxic dose of tomatine for an adult human would appear to require at least a pound of tomato leaves. These authors conclude that “the hazard in most situations is low.”

[John Pink]

they use to cupfuls of tomato leaves left in two cupfuls of water over night ,strain through a Muslin cloth ,then add two cups of water ,then spray to kill bugs. Aphids. .If tomatoes fall into fishtank ,could be reason fish become harmed.