Fiddler Crabs

[TheSmJ]

Around 3 or 4 years ago, my mom was bringing home some live plants from a pet store when I found a Fiddler Crab stow-away hiding in it. It turns out the plants were kept in the same tank as the crabs, thus the reason we ended up with one accidentally.

The little crab lived happily in our 29 gal. tank, along with other mild-mannered bleeding hearts, Angels, and a few different types of Tetras. It molted once every few months (which I understand is normal) and aside from us catching it basking on the top of the filter quite often, it made a fine edition to the tank.

Eventually, it managed to crawl out of the tank when we weren't home, and we found it dead in the opposite corner of the room months after it disappeared. Poor little guy...

Anyways, lately I've been thinking of setting up a Fiddler Crab exclusive tank. Holding 2 of them (a male and female as to avoid fights) in 1/3rd to 1/2 filled tank with plenty of land and filtered/aerated/salted water catered to their liking. I’d feed them sinking pellets, as for the type of pellet I’m going to ask what the pet store has been giving them.

I think a 5 gal. tank would be sufficient for just 2 Fiddlers. This sound about right?

Also, after reading that they can tolerate a few other creatures (such as large snails) I may add one later depending on how the crabs do.

So how does this plan sound overall?

 

[OrionGirl]

You may benefit from keeping it in mildly brackish conditions, and provide some areas where they can dig--a sandy substrate would probably work well, as you could keep it clean easier than a muddier one.

Make sure it's well covered--as you discovered, they are excellent escape artists!

For feeding, you can offer them some fresh veggies and meaty frozen foods as well.

 

[TheSmJ]

Yeah, I forgot to mention I was planning on using aquarium sand, allowing them to dig. Also, some nice places for them to climb out of the water (but not the tank) to dry off.

I've also heard that these guys tend to stay put when they have good living conditions (both water and dry land). The Fiddler we had beforehand had no such place, as it was simply a freshwater aquarium, and he was a rather unexpected edition.

How much aquarium salt do you add to the water for brackish conditions? I heard 1 tbs every 5 gal works, is this correct?

After looking at tanks (at my local PetSmart), it would appear the 10 gal aquariums are cheaper overall than the 5 gals. If I were to get a 10 gal, I'd have much more space, and a much greater drive to put things in... but what?

 

[OrionGirl]

I wouldn't put any fish in--crabs really can't be trusted with fish. There are exceptions, but for everyone who reports no problem, 5 report lots of fish deaths and injuries. Maybe some guppies--they will tolerate brackish conditions, and tend to stay at the top, away from the crabs. Plus, any babies would be a nice treat for the crabs.

I really encourage anyone making brackish/salt water to get a hydrometer. While volume amounts will get you close, testing with a calibrated hydrometer is a safer method.

 

[cdawson]

a really good substrate for fiddler crabs is refugium mud, if you give them land they can build their natural mud burrows in it. Something they can't do with just any normal substrate.

 

[TheSmJ]

I have not the slightest idea where to get that mud... I take it it's not mud I would find in my own lawn. Besides, I have no clue how to clean it (what IS clean mud, anyways?) and it sounds kinda messy... like it would make the water constantly "dirty" looking.

I'm still not sure what type of filter and heater to get such a setup... all the filters I've seen so far would easily suck up and catch such a loose subrtrate (such as sand, or mud).