20 gallon Mantis Shrimp tank [More pictures of 20 gallon tank with Peacock Mantis Shrimp]

Setup

Tank
20 gallon acrylic tank with built-in wet-dry setup during June of 2000. I previously had the mantis shrimp in my 29 gallon tank; the acrylic tank is a big improvement. Having an animal capable of cracking glass in a tank plumbed to my main reef display tank just wasn't a good idea. Watching my mantis break a thermometer in the glass tank was all the incentive I needed to setup a dedicated acrylic tank. The best thing about the new tank, aside from the fact that it is acrylic, is that there is plenty of room for a heater and thermometer in behind the tank in the wet/dry compartment. I haven't gotten around to putting black vinyl on the two sides of this tank yet. The acrylic seems to be less reflective than uncovered glass, so maybe I don't need to add the vinyl.

Filtration
Filtration consists of a built-in wet/dry filter with the biobale media from my CPR BakPak II filter. There are a few small pieces of live rock. This tank has a built-in protein skimmer that I've never been able to produce skimmate from, even with several fish in the tank. Oh well. The mantis can tolerate less than pristine water quality.

Substrate
Crushed coral, #10 grade, 3-7" deep (the mantis likes to dig and make piles). After the mess the mantis made during his three month stay in my 29 gallon refugium, I decided to buy the largest substrate I could find locally. #10 grade crushed coral may be too big; time will tell. In my opinion, a 4-inch or deeper substrate is essential because that's about how deep my mantis likes to dig his burrow. I originally put in 5-6" of crushed coral, althought the mantis has seen to rearranging that for me.

Circulation
Circulation is provided by the pump for the wet/dry, a Maxi-Jet 600. I added a length of vinyl tubing and a T-barb so the output of the pump enters the tank just above the substrate on the right side of the tank.

Lighting
2x15 watt normal output fluorescent.

Essential equipment
Quick hands and/or a long scraper for cleaning algae off the side of the tank.

Temperature
Temperature is maintained at 80-82 degrees.

Specific Gravity
1.025

pH
Haven't checked. Probably anywhere from 7.8-8.2

Livestock

A real looker, my Peacock Mantis Shrimp is the most loved and hated animal in my house.

There just aren't all that many critters that can safely live with a mantis shrimp. Aside from being a ruthless predator, my mantis shrimp is the ultimate bulldozer. During the three months mine was in my refugium, the only two things that didn't get moved and/or buried were two pieces of live rock that weighed more than five pounds. My 6" mantis moved every other piece of live rock, every snail shell every piece of rock rubble. Much of the macro algae got buried and died off. Some macro algae is growing out of a couple rocks but I keep find torn off pieces in the wet/dry, so it might not stay. My dying Sun Coral is in this tank.

• Macro algae
  
• Feather dusters
  
• Damselfish (for a limited time only...)
  
• Small hermit crabs
  
• Brittle or serpent star
  
• Urchins
  

Maintenance

Water changes haven't been done in the 20 gallon tank yet, but I imagine I will do them less frequently than in my reef or fish tanks. Probably 25% every two months. Mantis shrimp reportedly handle less than ideal water parameters quite well, so that's one perk!

Algae is quickly rubbed off with a piece of filter padding when the mantis appears to be sleeping. So far I've only had diatoms

Water top-off is probably the biggest chore with this tank, since enough water can evaporate in four or five days to cause the pump to run dry (causing the filter to stop working). I keep a gallon jug of deionized water next to the tank and pour some in when I remember.

Comments

Update! July 6, 2000:

Update: June 25, 2000 I moved the mantis into its own dedicated 20 gallon acrylic tank.

The substrate is #10 grade crushed coral, 5 inches deep. The mantis seems to have a harder time making burrows out of this than he did the aragonite. He also makes zero mess. I used the biggest size crushed coral I could get locally; probably I should have used a smaller size like #5 grade. It was kind of cool to see the mantis in a tank without a burrow - no place to hide. But from the little I have read, it seems mantis shrimp need a burrow to feel safe and be healthy, just like many fish do. I've added some empty snail shells and bits of rock; we'll see if that's enough burrow building material.

The mantis molted the day before I moved him out of the 29 gallon tank. His (her?) colors keep getting better with each molt. The top of its carapace was an ugly beige-brown a couple of months ago. Now much of it has turned a dark olive green, starting at the tail and moving toward the back of its head.

The macro algae I planted in this tank during the move isn't doing any better than the original macro algae in the 29 gallon tank. I think Halimeda algae or the larger variety of bubble Caulerpa would work; unfortunately neither is available in my area. The smaller varieties of Caulerpa I've been using get shredded by the mantis' daily roaming, and end up decaying in the filter.

I moved all the rocks in the old 29 gallon tank to get a look at the burrow the mantis made. The burrow more or less caved in when I moved the rocks, but it was obvious the mantis had put a lot of work into fortifying the walls of the burrow. I removed 15 snail shells and about 20 small pieces of live rock that the mantis had used to fortify the walls of the burrow. The mantis built the burrow by laying a foundation of rock/shells and then piling sand on top of that. In some areas there were multiple layers of rocks, shells and sand. The finished burrow was roughly a "T" shape, although the mantis blocked the right-side entrance, leaving two entrances/exits. The burrow was about 14" long and8" wide.

Original comments:

My mantis buried a few loose small mushroom anemones under sand in the old 29 gallon tank, but those attached to rocks faired ok.