Fiddler Crab storage tank

BContos · Jan 17, 2022

Who buys fiddler crabs in bulk and keeps them in a separate tank? Looking for low maintenance ideas on how to house these guys until they can be used as food.

A Young Reefer · Jan 18, 2022

I would go with a very basic setup just with the basic necessities. like a rimmed tank with a HOB and a heater. they are omnivores so I would recommend feeding them algae and pieces of fish or shrimp.

Shon · Jan 18, 2022

1: Land needed.

2: Cover; will climb cords, pipes, anything and escape.

3: Water gets dirty fast. I used an air pump, sponge filter. Only kept them week long between fishing, so it wasn't a big deal for me. I also had some live shrimp also..

4: They'll eat almost anything. I used old pellets. For your aquarium use, maybe give it a healthier diet since your using them as a food source.

5: Throw hand signs back when they do it. Not necessary, but entertaining.

BContos · Jan 18, 2022

Shon said:
1: Land needed.

2: Cover; will climb cords, pipes, anything and escape.

3: Water gets dirty fast. I used an air pump, sponge filter. Only kept them week long between fishing, so it wasn't a big deal for me. I also had some live shrimp also..

4: They'll eat almost anything. I used old pellets. For your aquarium use, maybe give it a healthier diet since your using them as a food source.

5: Throw hand signs back when they do it. Not necessary, but entertaining.

Thank you! I was thinking about using a storage tote and maybe some rubble of some sort for them to get out of the water but would be easier to clean vs sand. I have seen they make some low water filters for turtle tanks and was considering that for filtration. I just need something set up that is low maintenance most importantly

Ocypode sinensis · Jan 19, 2022

Fiddler crab can survive for a while in water, but usually they burrow on land, so you might wanna give them some sand and leave about a quarter to half an inch of water above it.
You can also lower the salinity of the water as they do well with brackish water.

BContos · Jan 19, 2022

Ocypode sinensis said:
Fiddler crab can survive for a while in water, but usually they burrow on land, so you might wanna give them some sand and leave about a quarter to half an inch of water above it.
You can also lower the salinity of the water as they do well with brackish water.

Ideally I would like to buy about a months worth at a time so I am thinking a tote with a turtle tank low water pump and some crushed concrete/rubble on the bottom on one side and rocks on the other they can get out of the water

Ocypode sinensis · Jan 19, 2022

BContos said:
Ideally I would like to buy about a months worth at a time so I am thinking a tote with a turtle tank low water pump and some crushed concrete/rubble on the bottom on one side and rocks on the other they can get out of the water

Yeah I think that will be fine, I've kept a lot of crabs but not fiddler crabs because their natural habitat (the tidal flat) was too hard to replicate.

BContos · Jan 19, 2022

Ocypode sinensis said:
Yeah I think that will be fine, I've kept a lot of crabs but not fiddler crabs because their natural habitat (the tidal flat) was too hard to replicate.

Thats what I am worried about but have not been able to find another species that is as inexpensive as these to buy in larger quantities. We are about an hour from where I can go to get them and I would rather not go a couple times a week lol

Ocypode sinensis · Jan 19, 2022

BContos said:
Thats what I am worried about but have not been able to find another species that is as inexpensive as these to buy in larger quantities. We are about an hour from where I can go to get them and I would rather not go a couple times a week lol

Indeed!

JNalley · Jan 19, 2022

Maybe you could consider making an acrylic baffle to put sand on one side, and rockwork leading up to the sandy landing and don't level the sand, instead make it rise slightly like a beach, this way you can put water over the baffle by about 1/2" and you have the best of both worlds? I've never kept them myself, but I like trying to problem solve and see if my ideas work :-D

Lineage03 · Jan 31, 2022

I just built a tank a couple days ago out of a 20 long. I have about 40 crabs in it now. I'll upload some photos later tonight. Essentially just got some acrylic to separate two sections. Used two pieces, one as a ramp (used textured for the ramp), and one vertical about 4-5 inches up to hold and for them to dig in on one side (so a small triangle of dead space in the center, thinking of trying to figure out a way to build an internal filter that could be housed in this space). Then placed some live and, and a small low water level filter on the other side with a few inches of water. Then in the water placed dry rock pieces and macro algae to give them some islands. I use a heater that goes below the tank to reduce cords. I had a smaller version of this and it worked great. Just top the water when you feed them, and mist the sand with RO water.

Lineage03 · Jan 31, 2022

Lineage03 said:
I just built a tank a couple days ago out of a 20 long. I have about 40 crabs in it now. I'll upload some photos later tonight. Essentially just got some acrylic to separate two sections. Used two pieces, one as a ramp (used textured for the ramp), and one vertical about 4-5 inches up to hold and for them to dig in on one side (so a small triangle of dead space in the center, thinking of trying to figure out a way to build an internal filter that could be housed in this space). Then placed some live and, and a small low water level filter on the other side with a few inches of water. Then in the water placed dry rock pieces and macro algae to give them some islands. I use a heater that goes below the tank to reduce cords. I had a smaller version of this and it worked great. Just top the water when you feed them, and mist the sand with RO water.

Here are some photos.

BContos · Jan 31, 2022

How much maintenance is this and does it smell? I keep reading their tanks smell nasty unless you change the water every other day!
Love this idea!

Lineage03 · Feb 1, 2022

BContos said:
How much maintenance is this and does it smell? I keep reading their tanks smell nasty unless you change the water every other day!
Love this idea!

I don't have any smell with a filter... if the filter goes out for any reason though, or you have dead ones left to rot it can get bad. I think the combination of live sand, a filter, and macro algae keeps it at bay though. Overfeeding will do it too, my last setup I noticed uneaten food would smell bad fast if it got wet so I'm putting a feeding dish in this one so that won't happen as easily (I used to just dump some on the sandy area but the sand would soak up into the food). Ultimately if you keep you water topped off (you will have evaporation if there's heat), and your filter media clean and changed when necessary I don't think you'll have a problem.

Maintenance isn't bad other than topping off water daily, feeding, and making sure your filter is good (doesn't take a big one because there's not much water in there). I also add some RO water to the sand side to keep it from completely drying out, enough so it's visible above the frame. Granted I've only been running one for about 4 months now...

I had a similar setup running for about 4 months now with zero smell noticeable, but my sand and water weren't separate so it was a constant battle of moving the sand back, and also anytime I'd refill the tank from evaporation their burrows would sink in. I know this would be natural if there were a tide, that's why I'd like to incorporate a built in filter that moves a small amount of water through it... or maybe put a pump in a box in the corner of the sand area and put it on a timer to act like the tide (it would fill to the water level when the pumps off, and lower when the pumps on... you'd just have to play with it to make sure the pump doesn't take too much water out too fast or you'll burn up pumps).

I'll keep you posted though, and let you know if I do any of the updates mentioned (I have TONS of ideas, whether I make them happen or not... lol).

Good Luck!

BContos · Feb 1, 2022

Lineage03 said:
I don't have any smell with a filter... if the filter goes out for any reason though, or you have dead ones left to rot it can get bad. I think the combination of live sand, a filter, and macro algae keeps it at bay though. Overfeeding will do it too, my last setup I noticed uneaten food would smell bad fast if it got wet so I'm putting a feeding dish in this one so that won't happen as easily (I used to just dump some on the sandy area but the sand would soak up into the food). Ultimately if you keep you water topped off (you will have evaporation if there's heat), and your filter media clean and changed when necessary I don't think you'll have a problem.

Maintenance isn't bad other than topping off water daily, feeding, and making sure your filter is good (doesn't take a big one because there's not much water in there). I also add some RO water to the sand side to keep it from completely drying out, enough so it's visible above the frame. Granted I've only been running one for about 4 months now...

I had a similar setup running for about 4 months now with zero smell noticeable, but my sand and water weren't separate so it was a constant battle of moving the sand back, and also anytime I'd refill the tank from evaporation their burrows would sink in. I know this would be natural if there were a tide, that's why I'd like to incorporate a built in filter that moves a small amount of water through it... or maybe put a pump in a box in the corner of the sand area and put it on a timer to act like the tide (it would fill to the water level when the pumps off, and lower when the pumps on... you'd just have to play with it to make sure the pump doesn't take too much water out too fast or you'll burn up pumps).

I'll keep you posted though, and let you know if I do any of the updates mentioned (I have TONS of ideas, whether I make them happen or not... lol).

Good Luck!

My idea on doing one was to get 3 storage totes.

Take one tote and do a partition like you have and drill holes in one side and leave the other side without holes. Then put that tub in another tub. Fill the side with holes with some water- what salinity do you keep yours at? And fill the other side with sand. Then on water change day- once a week?- ill pick up the top tote and set it inside the 3rd tote and refill the water. This will basically be a "feed out pen" for my predator tank so I do not want to overcomplicate things lol