I can't do this right now anyway, because my tank's not big enough, but I was curious if anyone else had ever put a Hammers Cobalt Blue Lobster in with their goldfish.
I'm always looking for things to put in with my goldfish that my sons would find interesting and I saw this type of freshwater lobster on liveaquaria.com

Here is what they say about it:

Care level: Easy
Max size: 5"
pH: 6.5 - 8.0
tank temp: 68-85F

They also state: "The Hammers Cobalt Blue Lobster is generally peaceful, except with its own kind. They will not typically bother fish, unless they are very small, and slow enough for the lobster to catch."

For food, it says they are omnivorous and mostly will act as scavengers taking food that is left on the tank bottom.

So on the surface it sounds good, but I have never heard of anyone doing it before. Any thoughts?

I'm not familiar with that particular crayfish or freshwater lobster but generally it is not recommended to keep crayfish with fish, they are predators as well as scavengers and can grab a fish while it is sleeping.

While they're sleeping? I never would have thought of that. Thanks for the info!

Yeah, if you have goldies or any other fish that sleep on the gravel the lobster will attack it.

Well, that's not a chance I want to take (My Ryukin does like his gravel naps...). Does anyone know of any other colorful/interesting fish that might work with goldfish? My wife doesn't like the compatible plecos or loaches and my kids aren't don't seem impressed by them.

How many gallons is the tank and how many inhabitants and sizes?

its a 29 gallon tank currently with 2 fancy goldfish. Anything I could put in there now would be great.

I am also thinking of going to a 55G in the next few months, probably with a third goldy, so I'm interested in what I could put in the tank at that point too.

Oop, I forgot sizes. Their bodies are about 3 to 3.5 inches without including the tail (about 5 with tail? I have trouble estimating).

If you dont mind a little chasing to begin with how about some minnows? They are small enough to keep out the way of the goldies and ive never had one that nipped a tail and are interesting to watch. You could easily get 6 to begin with and once you upgrade maybe some rosey red minnows as well?

That sounds perfect! I didn't know they were compatible. I'll have to see what the LFS has. Out of curiosity, how easy are minnows to care for and what type of food do they need?

Extremely easy to care for and they are really hardy. Feed the same as the goldies. Can you add a few tall plants even fake ones so the minnows feel safe and have somewhere to hide as the goldies will see them as food to begin with and then realise they cant catch them and leave them alone?

I've got a couple small plants already, but if I buy the minnows, I think I'll look into replacing them with a couple of bigger ones. They will have to be fake for sure, I don't have much of a green thumb and the fish are enough of a challenge for me right now!

Thanks again for the idea.

No problem, let us know how things go

any kind of crayfish or lobsters will diffinately try to catch and eat your fish,its their natural instinct to do that,i have a crayfish in with my 2 goldies but a friend of mine had him in with his oscar and the oscat attacked him and tore his claws off,they grew back deformed and he is unable to use them so there is no way he can catch my fish,otherwise he would...