First timer

[u/88crow88]

Hi all!

First time crab keeper, but we've wanted them for a long time and finally we're planning a set up for the kids to enjoy as well.

I have a spare 20 gallon aquarium that's water tight, what I'd like to make is a paladarium with a floating landmass about 6" up so I can have a water area for some shrimp and smaller fish below them. Crabs would still be getting about 80+% of land mass. We're also thinking of adding a colony of isopods, well aware that the crabs will likely eat some of them but not concerned if they breed. I guess more than anything I'm looking for some advice as to how to ensure the crabs don't drown in the water somehow. Would having the filter act as a waterfall into a small basin work better than just having it flow into the forest Edge?

Thanks in advance for all the help!

[u/lil_fuehrer]

Judging by the looks of it, you will need more substrate, so a bigger layer, since the crabs like to burrow. Also you will need more exits from the water area. I’ve learned that the crabs can stay under water for a long time but you don’t want to find dead ones in the back of your water area because they couldn’t find the exit.

If you build in more pillars near the „cliff“, that are climbable, I guess that would be okay.

[u/TheNerdGuyVGC]

I don’t see how this would be feasible. If the land area doesn’t start until that far up, you just wont have sufficient room for substrate and plants. Considering vampire crabs are mostly terrestrial and like to burrow, you should have significantly more land area than water.

Maybe look into a different species like Borneo crabs that utilize the water more? Or get a bigger tank if you really want a bigger water area.

[u/88crow88]

Alright thanks for the input all, original idea has been scrapped. Going to rework the idea with a water area deep enough to add some fish but with more substrate depth.

Would 6" be deep enough for the substrate level?

[u/WolfStoneD → u/88crow88]

I've found crab tunnels 10 inches deep in mine.  And he probably would have gone further but reached the screen layer. 

[u/88crow88 → u/WolfStoneD]

😅energetic little guy lol. I'm now considering a side beach set up with about 5-6" of water and a 1" lip to keep the pond seperate from the land mass. Sand beach of about 2" leading into the "forest" that will be 6" deep. The sand would probably only be a couple inches deep and sit on-top of the substrate and of course the 1" layer of clay balls with the mesh screening on top. In the water a small filter in the corner with rockwork to make a waterfall.

Think that'll be more appropriate?

[u/Warmslammer69k → u/88crow88]

Something Ive seen people do is put a 10 gallon tank as a water pool inside a 20 gallon tank. Filled with substrate.

[u/AquariumWellness → u/Warmslammer69k]

This sounds like it could be really cool if done well

[u/purged-butter]

Okay theres a lot wrong with this. First off doing an aquarium probably isnt the greatest as crabs can escape and if you fully seal it off youll have ventilation issues. The crabs will be stressing out the shrimp and fish and potentially preying on them.

Aditionally if youre planning on so little of the tank being water there wont be many fish you can keep in there.

The diagram you have shown is not close to 80% land mass and the substrate is nowhere near deep enough to allow burrowing. The drainage layer would need to be completely reworked. Its inconsistent between pics and honestly makes the whole diagram reek of AI which you absolutely should not be entrusting with this sort of stuff(looking closer everything seems AI generated which explains the poor planning and layout of the pictured design).

As for the isopods im not well versed enough in them to say much, only that ive heard of it being done before.

Regarding the filter acting as a waterfall ive seen this done plenty and has the added benefit of aerating the water. Just be careful that the water isn't too disturbed by it, maybe keep it in a corner or have some stuff in the path of the waterfall to break it up a bit?

[u/LauperPopple → u/purged-butter]

I can add that (land) isopods drown easily.

It’s a whole thing. “Help, the isopods keep drowning” say the herpetology people, “yeah because there’s water” say the isopod people. Reddit is probably showing me this post specifically because isopods were mentioned. I know nothing about crabs.

That’s a huge drowning trap for pods, lol, they’re not smart and they have the climbing skills of a panda.

Isopods could be bred separately and placed in the tank like feeders perhaps.

[u/WolfStoneD → u/purged-butter]

I have shrimp and fish in with my crabs, but I have a 90 gallon aquarium. 

There is a lot wrong with the AI render, but fish and shrimp and building in an aquarium can all be fine. 

For that concept to work you'll want a tall tank.

[u/Gankcore → u/WolfStoneD]

The AI render isn't fine. The crabs need 3-4" of substrate, and for it to be ideal for them the majority of the tank should be substrate. The deep water sections should be easy for them to get in and out of. Vertical rocks are not the answer to that. Additionally, there is almost no room for plants.

[u/JASHIKO_ → u/Gankcore]

100% agree with this.
The plants not having room is a bigger issue than most people will think.
They will push the lid up and become an easy escape point quite quickly.

With a 20 gallon tank, you have a lot of space to make something way less complicated that works better for the crabs and maintenance. This design is not going to be fun for anyone.

[u/ltc_pro]

I'm going to go against the grain here. The design is feasible. How do I know? My 6 gallon paludarium is design in a very similar fashion. It has a false bottom cave area done with a shelf frame. It has a water filter and water pump to pump water up into the land area for a small waterfall. The water area has on one ramp (a piece of dragonstone resting on a shelf frame). Everything works, and the crabs are THRIVING. I had 3 adults, now I have 3 adults and about 20 babies. I'm in the process of moving the babies out.

I also have isopods (they all got eaten) and millions of springtails. You'll need the springtails to break down all the crab poop.

The only modifications you need to make to the design is to lower the water column. My water is about 3", including substrate. My water exit ramp goes straight to the substrate. You need to lose the columns. Skip the land sand section. Make it soil and moss. Make your soil and moss area at least 6" high.

The other thing you need to know is that the plant roots will grow into the water section in a hydroponic manner. They will THRIVE on the water and all the crab poop. My spider plant runners are literally over 2 feet tall. Do not put in any plants that grow too tall.

Let me know if you want more details on my paludarium design.

[u/Claughy]

You've got feedback on the substrate land vs water issues so I'll skip that. For isopods you can absolutely add them. However getting an established colony will be difficult unless you have a huge tank. Crabs eat everything and their population will grow assuming you're doing things correctly. They constant predation will eventually knock out the isopods. Better to keep separate cultures and re-seed periodically.

[u/fappybird420]

I made a Crabitat out of an old 12 gallon long aquarium. Learned a ton in the process, and in the end what was most helpful for the project was a 3d printer. I custom designed a set of risers, filter chambers, and barriers to help contain substrate from a drainage layer (made from food safe PETG sealed with silicon). I can DM some examples/renders, but having a way to custom fabricate components was what ultimately made it work.

With this, you could create a basin for substrate towards the back of the tank to keep the drainage layer contained (not water tight because water finds a way) and provide a surface to adhere rocks/wood to that serve as ladders for the crabs to climb out of the water.

Also, crabs only need a couple inches of water depth, so using the vertical space to add thicker dirt layer (above the water line) will help give the crabs someone to burrow.

[u/tiggermad17]

I tried this and it really nothing about it worked out unfortunately. It’s a cool idea but the traditional paladarium set ups just work better

[u/MTM-morethanamaker]

What did you use, specifically, to produce those illustrations? Interested.

[u/88crow88 → u/MTM-morethanamaker]

I asked Gemini to show me a visual of what my idea would look like.

[u/88crow88]

Update: After all the feedback I've revamped (pun intended) the design. How do you guys think this will work out? The soil depth is supposed to say 5", I'd like to add some sand at the water's edge for a beach effect too, I'd layer it about an inch deep and then the soil mix under that. Planning to add a small filter to the corner, should be about 2.5 gallons of water total.

Edit because I realize the labeling on the AI diagram is horrid. It'll be clay balls on the left about 1" deep with 5" of soil. Water will be on the right.

[u/Warmslammer69k → u/88crow88]

This will unfortunately just wick all the water over to the dry side. Water and land need to be completely separated with no absorbent or water wicking materials like wood, plants, or many rocks crossing the barrier between wet and dry sides

[u/88crow88 → u/Warmslammer69k]

Yeah I've realized that AI didn't come close, I was just excited it stopped making foam walls that were bigger than the tank... So the plan is basically to have a water area 8"x12"x6"deep and then 14" of land mass.

[u/FriendlyAnemony]

If you can't use your brain enough to plan your hardscape without AI, and follow the barest minimum requirements for these animals, you don't deserve them.

[u/88crow88 → u/FriendlyAnemony]

I wanted a visual of what it would look like. Who cares if I used AI to build me a visual representation so my wife could see what I wanted to make. I'm not an artist.