Custom Structures for Vivarium- Help?

[cocoapuffs]

I'm pretty new to aquariums but eventually I'd like to be keeping, dwarf gouramis, orange delight shrimp, yellow shrimp, emerald green cory cats, a lyre tail dalmatian molly, neon tetras, and vampire crabs in a 37-55 gallon tank (preferably 55, talking to someone about one now). I'd be splitting the tank so it'd be 20-25 gallons of long space on the bottom half for all the fish and room up top for the crabs to hang out and burrow with a waterfall in the center to moisten the soil and increase humidity.

Custom structures I hope to have are:
-fake rock backing for top section
-fake rock to cover tubing for a canister filter
-ditch for holding soil/stuff for drainage(possibly a 6" pvc pipe cut in half, maybe heightened with styrofoam or other material and covered to look like rock
-wide/shallowly sloped spiral staircase of faux rock material or something similar for crabs to easily climb up and down
-platform extended from first few steps underwater to allow crabs to crawl around partially submerged

Here's a rough visual:


Though they'll likely be added later, I'd like the tank to be ready for the crabs before I add any fish. If anyone could recommend materials or a better way to do things that'd be great!

[limz_777]

crabs with shrimps ? dont think its good to mix them

[BFG]

I agree. The shrimps might be consumed by the fishes especially the shrimplets. But what I was afraid is that the bioload might be too much for such a small tank. I would advise on getting a 90 gallon or larger.

[cocoapuffs]

Everything I've read has said that vampire crabs are good in community tanks with shrimp and large snails, they just don't do well with other crabs and they might eat little snails.

[cocoapuffs]

I agree. The shrimps might be consumed by the fishes especially the shrimplets. But what I was afraid is that the bioload might be too much for such a small tank. I would advise on getting a 90 gallon or larger.

Like I said before, everything should be compatible, I'm not too worried about the baby shrimp because there should be plenty of hiding space for everything and I figured if they're breeding I can isolate them for a bit. I've also checked AqAdvisor a few times and to run a few tank size scenarios, using about half the 37 gallon water changes are at 34% a week and the tank is 81% "full", using half of a 55 gallon water changes are at 25% a week and the tank is 51% "full" (because there's so much more long space). So I wasn't worried about the bioload. For reference I plan on 2 vampire crabs, 5 orange delights, 5 neon tetra, 4 emerald cory cats, 1 dalmatian molly, 5 yellow shrimp, and 3 dwarf gourami. AqAdvisor and other research hasn't shown any problems between these species and there should be enough space for everybody to be comfortable.

[stormhawk]

If you do keep dwarf gourami, they do not really like super strong currents so you might have to provide some floating plants for them to hide under. The Molly would be a really bad idea to have with your invertebrates.