Tiny Ranatra

Yesterday I caught a Ranatra water scorpion that is barely over half and inch. It is now in two inches of water in a small vase with some duckweed to grip on and a mosquito pupae to eat. I an worried as it is very small and I was wondering if I should do anything special. Can someone share their experiences as the information on these insects is almost none.

You should prepare a larger home for it, a real aquarium. If you keep it in that small vase it is going to suffer from ammonia poisoning. Here is an article about ammonia's transition to first nitrite and then nitrate: http://www.fishkeepi...ing-article.htm You should have prepared a cycled home for your creature before you captured it. Since you didn't, you have to buy an ammonia test kit to measure the ammonia and know when to perform water changes.

I'm feel sorry for the poor thing. Ammonia burn is a painful way to die.

Edited by EricaWieser, 29 August 2011 - 04:09 PM.

Its only a temporary enclosure. I have a cycled aquarium but it contains tetras that are one inch long and a colony of guppies. I am also worried that the water may be too deep and there are fairly strong surface water currents form the HOB filter.

Are planning on letting the ranatra grow up and eat those tetras and guppies? Are they in there for food for it? If so, you could probably add some dense live plants (they're cheap on aquabid.com) to block current and hide the ranatra, and it might be okay in that tank. You'll definitely want to move it out of the vase before the ammonia rises to a measurable level from the rotting pupae.

Also, you might want to contact Dr. Jonathan Wright. He wrote this page: http://www3.northern...RT1/Waters1.htm

They are easy animals to maintain in an indoor aquarium. Use a gravel bed and freshly collected rainwater or pond water with plenty of submerged vegetation (Elodea, Callitriche, Myriophyllum, Ceratophyllum or Potamogeton are ideal). Plants can be secured beneath a few large stones. Make sure that some vegetation reaches to within 0.8 inches (20 mm) of the water surface allowing the water scorpions to breathe. Small nymphs and crustaceans provide ideal prey items. Use a well-lit location to promote plant growth but avoid direct sunlight. A few freshwater snails are useful to prevent the accumulation of algae on the glass.

It sounds like he has real life experience with keeping them alive in captivity.

Edited by EricaWieser, 29 August 2011 - 04:55 PM.

Raymond,

You did nothing wrong. Being air-breathing, I doubt your new friend will be too traumatized in its temporary home.

As you already know, they are predatory, so keep it away from any small critters that you care about, like your tetras and guppies. Also, from experience, they fly. Get some kind of porous cover on its container, especially if you share a home with people who are unimpressed with such a creature landing on the dinner table. Or in their hair.

A small fishbowl or mason jar could house your new pet for a good while. Give it something to cling to in and out of the water, do partial water changes every few days and it should be good to go.

Did I mention they can bite? Can be quite painful, cause swelling, so be careful. I have never been bit by a water scorpion, but I have by its close kin the belostomatid. Nasty.

And sit back and enjoy. I have never kept one long term, so I really don't know how well they hold up in captivity. A couple of weeks is about the longest I have kept one. It will probably want something more than mosquito larvae to eat. Mine was a little larger and partial to tadpoles, hence its short welcome in my home.

Have fun and keep exploring.

The Wright article is interesting. Sounds like a good setup for long term aquatic insect housing.

A friend of mine raised a bunch of these guys from eggs. They are poor swimmers and need something to cling to- live plants are nice, but artificial plants or sticks would work just as well. They will cannibalize one another, so anything up to their own size or possibly larger is fair game. They love daphnia and other microcrustaceans. Live blackworms, bloodworms, guppy fry, etc. would probably also go down well.