A recommendation for those looking to add aquatic insects to their aquariums

Looking for a really cool insect to add to your aquarium? I strongly suggest a water scorpion (genus Ranatra). Here's a pic for those who aren't familiar with these cool bugs!



Essentially all you need is some floating objects for the water scorpion to grip on, ans also so it can breathe through that long tube on the end of it's abdomen. You can offer one insect a week(watching them eat is AWESOME...it involves injecting a saliva that turns the insides to goo and sucks them out!) although I suggest removing all the legs of the prey item before offering it, otherwise it will twitch as it's being devoured, attracting other fish who will try and steal the water scorpion's dinner. And if you want to vary the diet, you can toss in the occassional fish(it has to be REALLY tiny though) once a month. Their stick-like appearance also helps them stay hidden from fish who may want to snack on it.

The reason I posted this is because I'm watching mine swim around right now...they're really cool.

They're fun captives! Although capable of taking fairly large prey, they also do quite well on a diet of live daphnia, mosquito larvae, and other small inverts. They embed their eggs in decayed, floating wood, with just two bristle-like projections extending from each egg into the water to betray their presence. A friend of mine once put one of these pieces of wood into a bucket and hatched out hundreds of the little guys; they rapidly cannibalized one another until only a few were left.

Yes, they are pretty cool. I kept one for a few months and he happily ate the occasional aquatic insect, but often also took live brine shrimp. Pretty neat to watch as they stalk the surface for prey. Predatory, underwater walkingsticks. doesn't get much better than that!

Never kept them, but they are cool. How do they do with filtration? Also, do you recommend keeping them with fish? From my experience, fish would get to live food much faster than a stalking Hemipteran. Seems like the type that would do good in a little 5-gallon with a sponge-filter and some plants, but I have no clue. I'm interested in hearing the set-ups you guys have kept them in.

Blake

I had some for a while with low-key fish like pirate perch and tadpole madtoms. I definitely would not recommend them for a tank with more energetic fish. They can deal with mild current as long as there is plenty of structure for them to grip onto, and in fact can often be found in slower parts of streams where there are lots of exposed roots or piles of detritus. Other long-legged predators can often be found here, such as the freaky-looking nymphs of the dragonflies Macromia (river skimmers) and Hagenius (dragonhunters).

Never kept them, but they are cool. How do they do with filtration? Also, do you recommend keeping them with fish? From my experience, fish would get to live food much faster than a stalking Hemipteran. Seems like the type that would do good in a little 5-gallon with a sponge-filter and some plants, but I have no clue. I'm interested in hearing the set-ups you guys have kept them in.

Blake

Like I said, they seem to hide very well from other fish, although my green sunfish and bluegill aren't big enough to make a meal out of him(well...maybe the green sunfish...but he ignores it). Here's a picture of my setup he's in. Yes, I know it's small, and I intend on transferring my fish to a larger tank later this month.



The water scorp likes to hang in the floating plants. I feed him one cricket every other week, which he takes from my hands(he also nabs freeze dried bloodworms when I feed my fish...which makes me wonder if he gets any nourishment whatsoever out of them). As I mentioned before, I remove all six legs so they cannot twitch enough to attract fish that try to nab it from him. Even when they try, they never have succeeded in robbing him of a meal. The filtration doesn't really affect him at all.

I'm sure there's some variation between species, but I should point out that I once lost a 2.5 inch pickerel to a 2 inch (not counting the snorkel) water scorpion. I wouldn't keep them with small fish you'd miss.

I'm sure there's some variation between species, but I should point out that I once lost a 2.5 inch pickerel to a 2 inch (not counting the snorkel) water scorpion. I wouldn't keep them with small fish you'd miss.

My water scorpion used to show some interest in killifish an inch or less, but has never chased them down. In my opinion, healthy fish can avoud being eaten by inverts.

I saw one these guys eating a three inch rainbow trout one time, but this one was a monster. They make me think of an impossible hybrid of a walking stick and a praying mantis. Awesome insects. How long do they live? Can they fly/walk on land? Do they bite people?

I saw one these guys eating a three inch rainbow trout one time, but this one was a monster. They make me think of an impossible hybrid of a walking stick and a praying mantis. Awesome insects. How long do they live? Can they fly/walk on land? Do they bite people?

I've heard they can reach 4 inches. I hope mine gets that large... The hybrid between a walking stick and mantis is also exactly what I think of when I see these. Not sure how long they live. I assume a year or two. They can absolutely fly and walk on land. If you keep 'em, have a lid! My friend told me he knew someone who had a tankful of these guys and woke up one morning to see they all flew out and were on the ceiling! And I've heard they can bite people...if not merely pinch with their front pair of raptorial (LOVE that word ) legs.

Yeah, they can tag you. It's not as bad as some of the other aquatic hemipterans, like belostomatids, naucorids, or some backswimmers; I'd say the bite is a little worse than a sweat bee sting. But bites are rare. They're not flexible so you would have to be very careless when handling one to allow it to bite you. I've never been bitten by one while wading despite spending lots of time in places where they are abundant. My sole Ranatra bite was achieved deliberately, as I wanted to see what it felt like.

The water scorpion family contains some more robust insects, such as Nepa sp.; these water scorpions are more suited to grabbing large prey and so are probably less appropriate for a tank with fish.

Now thats what i call a REAL scientist.

I've never been bitten by one while wading despite spending lots of time in places where they are abundant. My sole Ranatra bite was achieved deliberately, as I wanted to see what it felt like.

Hemipteran bites build character! Except for Triatoma; keep away from those things. You don't want Chagas' disease!

Hemipteran bites build character! Except for Triatoma; keep away from those things. You don't want Chagas' disease!

Hey Newt you seem to have a better understanding of these guys than I do...what's their lifespan?

The ones I have kept lived a few months, but I don't know how old they were when collected. I would guess most of the bigger aquatic bugs have a one-year life cycle, but that doesn't mean they can't live longer in captivity.

On a related topic, getting bit by giant water bugs, that sucks. I have had one do it and I smashed that ugly thing and yelled like the Predator was attacking me. Made me unwilling to swim in non-swimming pool water for a while. Those ugly things make great pike and bass bait, though.

I smashed that ugly thing and yelled like the Predator was attacking me.

"you are one ugly mother ...."

I have never been bit by water scorpions or those beetle things, but if one is in my net i whip it out ASAP! I am curious to keep one though, could be neat to see bugs eating fish. I would die if I came home and found them on my ceiling though. I was thinking of having a screen lid invert tank come spring, and this might just tip me in that direction. thanks for the info.

Edit: oh my gosh i spelled "neat" wrong

Edited by Burbot, 06 December 2009 - 11:21 AM.

"you are one ugly mother ...."

I have never been bit by water scorpions or those beetle things, but if one is in my net i whip it out ASAP! I am curious to keep one though, could be neat to see bugs eating fish. I would die if I came home and found them on my ceiling though. I was thinking of having a screen lid invert tank come spring, and this might just tip me in that direction. thanks for the info.

Edit: oh my gosh i spelled "neat" wrong

Imagining spindly legged invertebrates crawling along my ceiling, now I'm thinking of Alien facehuggers. I like insects, but hate the idea of huge ones that bite. Or sting.

"you are one ugly mother ...."

I have never been bit by water scorpions or those beetle things, but if one is in my net i whip it out ASAP! I am curious to keep one though, could be neat to see bugs eating fish. I would die if I came home and found them on my ceiling though. I was thinking of having a screen lid invert tank come spring, and this might just tip me in that direction. thanks for the info.

Edit: oh my gosh i spelled "neat" wrong

If you're going for aquatic inverts, I would strongly advise against a screen lid. Just saying.

If you're going for aquatic inverts, I would strongly advise against a screen lid. Just saying.

really? why? Don't just say, I would like to know why a screen lid is such a bad idea. i can't imagine a regular hood lid keeping them from escaping.