4g vs 8g biocube for a small mantis

ManderTang · Apr 19, 2013

So I get that mantis shrimp aren't exactly coveted pets for saltwater hobbyists, but my fiancee fell in love with a little green guy at the LFS about a month or so ago. She insists on visitation and has talked about him non-stop. With The Oatmeal published the comic recently her love was only solidified. It's pretty adorable.

Anyway, I've decided to surprise her for an early anniversary present. We've chatted with the owner of the LFS (reef store) multiple times now, but it was a buddy of mine who convinced me to "take the plunge". I have no experience with salt, but I've done discus and various community tanks, and from what I've been told, "If you can do discus, you can do salt" (I hope!).

I stopped in to see the owner of the shop today and he has a 4g biocube that is set up and cycling with sand, a rock, and a small mushroom. He can acclimate the little guy into the cube and I would purchase the entire setup (and the shrimp).

However, I found an 8g biocube on Craigslist. Would it be better to purchase that and purchase the live sand and rock separately and set up the system on my own? The 4g biocube does not have a protein skimmer, but the LFS owner said that was not necessary. My buddy agreed and said it would be better to go with the new setup since it's my first time. My research seems to contradict this, but I tend to over-analyze and read too much into things. Is the 4g appropriate for now for a first timer and for my fiancee's shrimp-love? The owner said a small damsel could also go in there eventually too if we wanted (I am aware this doesn't always work out with mantis shrimp).

In addition to the setup, is a refractometer better than a hydrometer? I am also not sure exactly what the step-by-step procedure is for water changes for a biocube of this size and maintenance. Over the years caring for freshwater, I became accustomed to doing things different "against the grain" and worked very well. Any tips would be appreciated.

NanaReefer · Apr 19, 2013

IMO go with the 8g..bigger is always better.
Refractometer hands down over a hydrometer.

She may love it now but....has she seen it eat yet? What do you plan on feeding it? Are you aware of the max size? What species is it?

ritter6788 · Apr 19, 2013

Need to know the species of mantis before recommending a tank size.

Some stomatopods are longer than an 8 gallon biocube.

Bigger is always better though.

Cheap 10-20 gallon Walmart or petco tanks make good homes for some small hitchhikers mantis.

danimgale · Apr 19, 2013

From what I have read you will want to make sure that what ever tank you put him in isn't glass. I have heard that they can actually break glass with their "punch". I believe acrylic tanks are best for them but I'm not sure. As far as using a new cube vs a used one that is all preference. When you get a used tank you always run the risk of getting one that leaks or has other issues. I myself would also probably go with the new tank for my first set-up especially if the lfs is willing to help you get it started. Like I said though, it's all preference. If you are wanting a bigger tank and want to take the risk with the used one then go for it. Just keep in mind you may need to do some repairs if something isn't working right. If you aren't doing a ton of different corals a protein skimmer isn't really necessary. I have a 28 gal nano cube with a few various corals and don't run a skimmer.

Refractometer vs hydrometer is also preference. I have both and tend to just use my hydrometer because it is quick and easy (though not as accurate). You will want to change about 10% of your water a week. Step by step water changing is basically turn off pumps, scrub your glass and rocks for algae, take out some tank water (I use a piece of plastic tubing and get a siphon going and use it to suck up any obvious yuck in the tank and once I feel I have things sucked up I then use a big bowl and scoop out the remainder of the water I want to change), and replace with clean salt water that is at the correct temp and salinity, then turn your pumps back on. You will want to use RO/DI water to prevent extra nitrates and stuff from getting in your tank that can come from tap water and mix in the amount of salt recommended on your salt mix to reach your desired salinity.

Maintenance is basically check your water parameters (ammonia, nitrite, nitrate, etc.) at least weekly, top off with fresh RO/DI water daily for any evaporation that might occur, and change out any media that might need to be replaced according to the media's instructions or what ever schedule works best for your tank.

I'm sure I'm missing a bunch of steps but you get the big picture. You will get to know your tank and your shrimp and know what needs to be done when. Everyone does things a little different.

These tanks get extremely addicting and don't be surprised if you soon are upgrading to a full blown salt tank.

ManderTang · Apr 20, 2013

Thank you for the replies and I greatly appreciate the run-through as far as water changes go.

The mantis shrimp is this one: http://www.ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/species.php?name=g_falcatus
Recommended tank size for an adult is about 5 gallons. We have both seen it eat. I was planning on feeding mysis shrimp, krill, small snails and crabs occasionally, along with small pieces of frozen shrimp or scallop. This guy has been in an aquarium for some time now. He hitchhiked into a customer's setup and it took them quite awhile to figure out he was in there, let alone catch him!

danimgale · Apr 20, 2013

Good luck with him. There is a peacock mantis at the lfs that I'm trying to talk my husband into setting up a tank for. It is so pretty!

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