Murderous Dwarf Crayfish!

[Dovey]

Beware. These are crayfish. They may be small, but they are still killers! They are NOT just bigger dwarf shrimp! I just saw one run into its cave with a cardinal Tetra in each pincher. That's more than $8 worth of fish. For that I could feed myself dinner. Perhaps I'll be having crayfish.

 

[chanda]

Yeah.... they'll do that. We used to have a crayfish (named "Gumbo") who devoured the guppies with whom he was sharing a tank.

Shall I offer you some filé powder or blackened seasoning?

 

[Galapoheros]

Perhaps I'll be having crayfish.

Ha, yeah crayfish are pretty brutal predators and scavengers, there aren't many animals they can live with. I have a book about crayfish, covers Texas sps. When I was a kid I found what's called the devil crayfish http://www.flickriver.com/photos/137489154@N02/22853678825/ That was before the internet, I didn't know what I had found but it sure looked cool under the UV tank light. But yeah, I guess they do best alone.

 

[Dave Jay]

Was it @Godzillaalienfan1979 that was asking about crays and shrimp a while back?
Even if shrimp and crays can't catch fish at night they will nip pieces of fin off to eat.
One observation of mine is baby American cichlids know how to deal with them instinctively, they dart in, pick off the eyes then wait for them to die (or not, as long as they're blinded). Then they know to attack the soft spot where the tail meets the carapace and they know that the claws can't reach them there. I've seen cichlids take down crays many times their own size with that method.
Our (Australian) aquatic tortoises know how to deal with them too, coming in from behind , a foot holding the carapace down and attack the join to sever the tail from carapace always staying above and behind so the claws can't reach them.
Fascinating to watch baby animals using their instincts.

@Dovey rest assured the fish will have the last laugh when the crays moult!

 

[Dovey]

Was it @Godzillaalienfan1979 that was asking about crays and shrimp a while back?
Even if shrimp and crays can't catch fish at night they will nip pieces of fin off to eat.
One observation of mine is baby American cichlids know how to deal with them instinctively, they dart in, pick off the eyes then wait for them to die (or not, as long as they're blinded). Then they know to attack the soft spot where the tail meets the carapace and they know that the claws can't reach them there. I've seen cichlids take down crays many times their own size with that method.
Our (Australian) aquatic tortoises know how to deal with them too, coming in from behind , a foot holding the carapace down and attack the join to sever the tail from carapace always staying above and behind so the claws can't reach them.
Fascinating to watch baby animals using their instincts.

@Dovey rest assured the fish will have the last laugh when the crays moult!

NOT HELPING!

 

[Galapoheros]

I grabbed some native cichlids out of a rocky river during a drought, put the in my aquarium, nothing else survived, those things are brutal. I would keep those alone like crayfish.

 

[Dovey]

Yup. Native fish are Killers, too.

Except flag fish and other killies. And a few suckermouths.

So what do you think I should put in that tank. I have rescued all of my Wii sweet-tempered nano fish, Cardinals, sparkling gouramis, Etc and even pulled two of the baby plecostomus I was starting in there. Just in case.

What can live with the little crayes without getting et or biting their little eyes out?

German Blue Rams?

I'm tempted to put pea puffers in there and just sit back and watch the steel cage Deathmatch. Little pinchy devils! If they weren't so darn cute, there'd be trouble.

How about honey gouramis? Flag fish? Theyre fairly muscular and also fellow grazers of algae. No dangly bits to grab. Oscars? Kidding. Kidding about the Oscars.

 

[Dovey]

Oh, forgot to say, it's an old fluval Chi 5 gallon portrait tank. Tall but small. Fish can't be too frantic or energetic. No danios, etc. And under 2.5 inches. My own filtration system, sponge filter in the lower corner. No lid. No silly fountain fixture thingie...just a nice glass cube. Planted tank. Black sand substrate.

I have naturally highly mineralized water from our well that is very alkali, but I also have a distilling system and can drop pH by mixing tap water with my distilled water. It's alkali from the well, but well-buffered.

And currently it's housing 5 sociopathic dwarf crayfish. Lots and lots of hidey-holes, rocks, logs, half terracotta pots from the fairy garden section at Hobby Lobby.

Gold barbs (Puntius sachsii)? One of the dwarf gouramis?

 

[Dave Jay]

Dare I say nothing?
Personally I'd try leopard danios, top dwelling, fast, and they have that 'natural' look but aren't just grey fish.

 

[Dovey]

I thought about leopard danios. That's a really interesting idea. They're a little bit more settled than the other danios, and they're not too big.

 

[Dave Jay]

I thought about leopard danios. That's a really interesting idea. They're a little bit more settled than the other danios, and they're not too big.

They are much nicer than other danios in my experience, much more peaceful , and I like that they look like mini trout or something, pattern, colour and that sheen when the light hits them right. There's other fish that might be faster, but to me it seems a good bet, and it'll look natural if you do it right.

 

[Godzillaalienfan1979]

Was it @Godzillaalienfan1979 that was asking about crays and shrimp a while back?
Even if shrimp and crays can't catch fish at night they will nip pieces of fin off to eat.
One observation of mine is baby American cichlids know how to deal with them instinctively, they dart in, pick off the eyes then wait for them to die (or not, as long as they're blinded). Then they know to attack the soft spot where the tail meets the carapace and they know that the claws can't reach them there. I've seen cichlids take down crays many times their own size with that method.
Our (Australian) aquatic tortoises know how to deal with them too, coming in from behind , a foot holding the carapace down and attack the join to sever the tail from carapace always staying above and behind so the claws can't reach them.
Fascinating to watch baby animals using their instincts.

@Dovey rest assured the fish will have the last laugh when the crays moult!

Very interesting post actually. Thanks Dave!

 

[Godzillaalienfan1979]

and also, i'm really not sure much could live with Crays without being attacked or vice versa. Maybe try schooling fish? I dunno, there would be a ton of them so i'd assume if one or two were eaten there'd still be more.

You could also try a large Plecostomus, but i'm no aquarium expert so I don't know. They have armor plating so that'd protect them from any huge wounds, but aren't their fins still vulnerable? Again, take my suggestion with a grain of salt, i'm no aquarium expert.

 

[Dovey]

These are tiny crays. They don't even get 2 in. They're going to poke at smaller fish or drippy fins, but anything big can just give them a thwack with a flip of their tail. They leave my 2 inch baby plecostomus well alone because they have enough armor plating. I'm about decided on 6 or 8 Hyphessobrycon margitae. They school, they get 2 inches big, and Advanced Fishkeeper describes them by saying they look like a ruby and a sapphire had a love child. Hard to beat that!
https://www.advancedaquarist.com/blog/crazy-beautiful-new-tetra-species

 

[MikeofBorg]

The little orange ones? They can be little bullies. Had one of mine grab my betta by the fins and rode it to the surface. The betta was going is spirals trying to get it off it.

 

[Godzillaalienfan1979]

Crayfish will still nip at their fins regardless. If those things get 2 inches long and the dwarf crays get 2 inches long, then Crayfish will still probably kill them.

Bottom line: you do whatever you want to do-i'm not trynna stop you-but crayfish really aren't good with fish, i'd stop while I was ahead if I were you and just keep your dwarfs in a separate enclosure, and save yourself the heartbreak of your fish dying. Also I remember I said schooling fish might be fine, but you'd need alot more than 8 to keep them safe. Dwarves and those new tetras are both super cool, but just don't seem compatible to me. If you really want invertebrates with your fish, get Thai Micro Crabs, some type of PEACEFUL shrimp (if you wanna retain the bright colors, cherry shrimp/crystal shrimp are awesome!), or some elephant/assassin snails.

Again, I only have a small bit of experience with aquariums-I assume you have more-so take my advice with a grain of salt.

 

[Dovey]

You know I've had these guys before. I don't know what the problem is suddenly. I think I've just got a line of bloody minded ones in. Someone said either they're peaceful or they're Killer's, and I think that's true.

Before I decide anything, I think I'll just wait a day or two. Let everybody just simmer the heck down.

 

[Godzillaalienfan1979]

You know I've had these guys before. I don't know what the problem is suddenly. I think I've just got a line of bloody minded ones in. Someone said either they're peaceful or they're Killer's, and I think that's true.

Before I decide anything, I think I'll just wait a day or two. Let everybody just simmer the heck down.

Yeah sorry about that lmao. I think the thing here is that people are (incorrectly) assuming you're trying to mix incompatible species together despite their advice-which you're not. So yeah my dudes, just chill.

 

[Dovey]

"Compatible" is actually a pretty tricky word when you're talking about these crayfish if they are fish hunters. If you were talking in terms of from the same biotope, every species you mention would either be a predator or prey. Which is too bad, because I love neat little biotope aquariums.

Nope, if I'm going to have fish in this tank, it's going to have to be something quick, high up in the water column, sleek and without any wavy bits, and small mouth so it doesn't eat crayfish. And frankly, the "high up in the water column" part doesn't even really remove the difficulty, because I have seen one of these guys fishtail himself up to a floating piece of wood and hang on near the surface to hunt.

Now what I don't understand is why folks think other invertebrates might be safe in the tank? If these guys will take down a fish larger than themselves, why would they not go after an Amano or a flower shrimp? That would be good to know. I'm leaning away from fish and toward various kinds of invertebrates if I could get away with it. I have to say, 24 hours without losing another Cardinal has been nice!

Clams. Clams would be safe.

 

[Godzillaalienfan1979]

"Compatible" is actually a pretty tricky word when you're talking about these crayfish if they are fish hunters. If you were talking in terms of from the same biotope, every species you mention would either be a predator or prey. Which is too bad, because I love neat little biotope aquariums.

Nope, if I'm going to have fish in this tank, it's going to have to be something quick, high up in the water column, sleek and without any wavy bits, and small mouth so it doesn't eat crayfish. And frankly, the "high up in the water column" part doesn't even really remove the difficulty, because I have seen one of these guys fishtail himself up to a floating piece of wood and hang on near the surface to hunt.

Now what I don't understand is why folks think other invertebrates might be safe in the tank? If these guys will take down a fish larger than themselves, why would they not go after an Amano or a flower shrimp? That would be good to know. I'm leaning away from fish and toward various kinds of invertebrates if I could get away with it. I have to say, 24 hours without losing another Cardinal has been nice!

Clams. Clams would be safe.

Well, if clams get sick and die, their remains poison the tank. They're buried most of the time, so it'd be hard to tell.