Looking For A Cold Water Herbivore Fish

[purple_drazi]

I've got a science teacher who wants my daughter #2 to bring a guppy to school to show the kids a closed bio-system.
No heater, no treated water, no food except the plant that's in the jar.

The last time I did this (when daughter #1 was in the class) I took an aquarium in, heater, water conditioner and all, set it up for him and explained to him that guppies can't live off of the algae and plants alone. The guppy died from the stress anyway. Not doing this again.

It's daughter #2's turn to bring a fish in so I'm looking for an herbivore that can live in an unheated jar.
Is there such a fish?
I thought goldfish but they're omnivores and need their flake food, brine shrimp or whatever.

 

[nosoup4you]

How about some herbivorous snails?

 

[purple_drazi]

How about some herbivorous snails?

Yeah, that's the kind of thing we're looking for, thanks, but we already have some snails. What we really need are fish to substitute for the guppies.

 

[saz326]

What about water fleas (daphnia)

They will eat algae/green water. Start up the jar first so that some algae grow, then put some daphnia in.

Cant think of any fish suitable - unless the jar is going to be kept warm-ish..... maybe then a small otto?

...just researched. Otto (small suckermouth fish) will get to 5cm and eats algaes - so won't eat the plant as it grows. Not suitable I'm afraid!

 

[Schmill]

A truely enclosed system is something that some aquarists will strive for for years, trying to get that perfect balance between fish and plants for the ultra-low mainentance tank, but I think they still need food. It's just not something I can see happening in a jar with a little bit of plant and a complex creature such as a fish. Even balancing the oxygen requirements / toxic gas 'off gasing' would be near impossible, unless the 'closed' bio-system isn't actually closed, but open to the free air?

 

[loubega]

whilst out christmas shopping with a mate, we were in one of those generic shops that open up every christmas and sell the usual gifts that people dont want and we saw one of these,

its marketed as a ecosphere - closed system, it requires no feeding or anythings as it is totally self contained....maybe worth a look, it contains shrimps, algae and bacetria...

take a peek

http/www.tropicalfishstore.com/Ecosphere.htm

and

http/www.ecosaqua.com/Ecosystems_and_Ecocosms.htm

 

[purple_drazi]

What about water fleas (daphnia)

They will eat algae/green water. Start up the jar first so that some algae grow, then put some daphnia in.

Cant think of any fish suitable - unless the jar is going to be kept warm-ish..... maybe then a small otto?

...just researched. Otto (small suckermouth fish) will get to 5cm and eats algaes - so won't eat the plant as it grows. Not suitable I'm afraid!

Unfortunately, we don't have time to let algae grow.

The jar is kept under two uncovered fluorescent lights to help the plants with their photosynthesis, not for heat.

A truely enclosed system is something that some aquarists will strive for for years, trying to get that perfect balance between fish and plants for the ultra-low mainentance tank, but I think they still need food. It's just not something I can see happening in a jar with a little bit of plant and a complex creature such as a fish. Even balancing the oxygen requirements / toxic gas 'off gasing' would be near impossible, unless the 'closed' bio-system isn't actually closed, but open to the free air?

Although the idea is that of a closed ecosystem, it isn't actually totally closed. I'd call it semi-closed. The jar is covered, but air is able to enter and leave.

whilst out christmas shopping with a mate, we were in one of those generic shops that open up every christmas and sell the usual gifts that people dont want and we saw one of these,

its marketed as a ecosphere - closed system, it requires no feeding or anythings as it is totally self contained....maybe worth a look, it contains shrimps, algae and bacetria...

take a peek

<a href="http/www.tropicalfishstore.com/Ecosphere.htm" target="_blank">http/www.tropicalfishstore.com/Ecosphere.htm</a>

and

<a href="http/www.ecosaqua.com/Ecosystems_and_Ecocosms.htm" target="_blank">http/www.ecosaqua.com/Ecosystems_and_Ecocosms.htm</a>

Shrimps would work wonders, but we can't use them.


I'm starting to wonder if there are any cold water herbivores that are small enough to fit in a jar.

 

[Honeythorn]

Quite frankly I'm disgusted anyone would want to attempt something so unproven on a living thing . An unheated jar with a bit of plant in it is a miniscule deathtrap and nothing more. The plant won't use up all of the waste produced by even one fish, and even in the wild rainfall and flooding refresh water sources, rivers and lakes. Would water changes be done on this jar? Frankly I very much doubt you will find any sort of fish small enough for such a project and it's horrific and cruel to try it in the first place.

 

[england]

is it going to permantley be closed in a jar without feeding it?
or is it a day showing you pet project? if yes to the latter you could probally get away with a betta in a heated classroom

 

[Honeythorn]

A single day to show a fish will do little harm, but to try and keep the fish in such an environment for an extended length of time purely to see if you can or how long it lasts before dying of maltreatment is unthinkable, science or no science.

 

[england]

thats what i ment
what about those water monkey things, they could grow them from a egg feed them and watch them grow

 

[Tokis-Phoenix]

I've got a science teacher who wants my daughter #2 to bring a guppy to school to show the kids a closed bio-system.
No heater, no treated water, no food except the plant that's in the jar.

The last time I did this (when daughter #1 was in the class) I took an aquarium in, heater, water conditioner and all, set it up for him and explained to him that guppies can't live off of the algae and plants alone. The guppy died from the stress anyway. Not doing this again.

It's daughter #2's turn to bring a fish in so I'm looking for an herbivore that can live in an unheated jar.
Is there such a fish?
I thought goldfish but they're omnivores and need their flake food, brine shrimp or whatever.

There are no fish that can live in a "jar". The smallest minimum Aquarium size for any fish i know is a 1-2 gallon tank for a single betta (also known as Siamese Fighting fish), they're hardy fish which don't require filtration or heating (as long as the tank is kept at a decently warm room temperature) but are not herbivorous fish (they're omnivores/insectivores).

What does the school hope the students to learn from the project anyway? Sounds like a pretty flawed and unnecessary project that will just end up with a lot of fish dying.