Lunch as a pet?

[DWhatley]

There are hermits that get quite large and keeping some of them can be a hobby in itself. As long as they can live in shells no larger than the size of your thumb they should be no problem for any octopus. Hermits living in shells the size of your fist may still be octo lunch but size is always a factor in the preditory world. Be aware that not all octopuses will eat hermits or may only eat them when first intoduced to the aquarium. Small crabs and shrimp are the most often eaten common foods.

 

[cuttlegirl]

Ok, I would recommend getting an RO/DI filter. It is much better to remove the chemicals by filtration than by trying "chemicals in a bottle."

What are you using to measure the salinity? Some of the hydrometers that you purchase at the pet store are not very accurate.

Also you should premix that salt with the water before you put it in the tank. Either get some 5 gallon buckets or a large plastic container. Some people use garbage cans. Measure the water and the salt before adding to the container.

 

[hlywkar]

by no size bigger than my thumb, I assume you mean length? not diameter?

so you think small crabs and shrimp would be better as clean up crew?

Ya I am thinking about getting a R/O ... not sure how to go about doing that in korea though, or the price. That will have to wait a bit at first though.

to measure salinity I am using a plastic hydrometer for specific gravity by CORALIFE called DEEP SIX. put in the water, over flow goes out the bottom, and a little needle goes up .

 

[cuttlegirl]

That one is not very accurate - if you can, you should get a refractometer.

 

[DWhatley]

I like the deep six hydrometer the best of the ones I tried but with any of the weighted needle kind, it is a must to keep them rinsed with fresh water, set them on a flat surface and wait 30 seconds. Doing it this way, you should see consistent readings and the needle will work well for a long time. For hobby aquarium use, they are quite satisfactory (IMO) as long as you keep them free of any kind of build up that can change the needle's ability to move freely. The ocean's salinity will vary more than the error rate with a properly working unit.

I am glad you are thinking about an RO/DI (the DI sand takes out copper and other metals), I know this adventure has been far more expensive than you first envisioned but I am glad to see you are working through setting up an aquarium.

Hermits are helpful, whether or not they become food. For sizing was was talking about the shell (not the creature) and both length and thickness of your thumb is a good go by for max shell size (they change shells as they grow). Anything smaller is fine and the little ones will get into smaller places. I would consider adding small crabs in addition to hermit (you don't have to have one kind of clean-up crew and a mixture is usually best so all three are welcomed).

 

[DWhatley]

Sorry for the counter Jenn and we were posting at the same time so I did not intentionally negate your post but I actually like this unit and have had it for several years. I have tested it against others with the floating needle (but not with a refractometer) and now only use this one. Ocean salinity varies greatly in the shallower waters and the small amount of error with a hydrometer does not seem to have any effect on any of my tanks.

 

[hlywkar]

and you think wait two weeks to put any of those guys in? I am fairly certain I can get tiny crabs (about the size of a nickel) at the market for really cheap... as well as shrimp.

The hermit crabs I have found online for as low as $1 per.

 

[DWhatley]

Remember that on-line means shipping extra and you will likely have to find a supplier in Korea as most US suppliers don't have permits to ship live to you. Nickel sized crabs are good. Shrimp size for food will vary with the size of the octopus. From the other photos I have seen, full sized eating shrimp would be about right. SueNami really seems to enjoy catching them live and we are down to our last one without a good way to get more (we brought these home from vacation). If you have them locally at the market (we have tried our Korean market but they only have live large crabs and crayfish) and go by once a week you should be in excellent shape for food.

Yes, wait the two weeks to let the tank settle.

 

[hlywkar]

well. surprisingly hermit crabs are sold every where around here... the site I saw was a Korean site.

 

[hlywkar]

Took out the flashlight last night... saw a bristle worm again, not sure if it was the same one or not... it had white bristles though.

Also saw a couple tiny bugs. really thin, and about 3 mm long. moving REALLY fast. they also had antennae

 

[bluespotocto]

The little thing with antennas is most likely a little amphipod. They usally come out of the rocks and stuff.

 

[DWhatley]

Another visible creature that you should start seeing (if you will leave it IN the water ) are tiny shrimp like creatures that will be either amphapods or copapods. Often new tanks will have a bloom of these and you will see little "bugs" everywhere for a week or more.

 

[hlywkar]

went to the beach today... It so happens that hermit crabs are incredibly easy to catch at the beach.

What about max crabs per tank?

can hermit crabs and the little tiny flat crabs coexist in one tank?

what would I feed these guys? shrimp too?... or just let them eat the algae?

also, should I be aiming to stack my rocks more, making more room for open sand, or spread them out more? Right now I have them spread out. And I am noticing I don't really have a lot of free ground space open.

 

[hlywkar]

Hey... also I noticed last night, I have some of my 'deader looking' rocks turning brownish(They were white before). Is that bad? I assume it's algae. Should I adjust the length of light for my tank?

 

[DWhatley]

The hermit crabs need to eat meaty foods AND you want to increase the bioload in the tank so you will want to feed them. I have no clue on the max hermits per tank. When people first started experimenting with LR, the successful tanks were loaded with hermits but the LR went directly from the ocean to the tank and was loaded with all manner of food. Since then we have learned to use an assortment of cleanup critters and even uncured rock is much cleaner before it is put into a tank. Hermits will get aggressive if the food supply is too low and start picking on each other and anything else in the tank (like seastars and serpent arms). You will also want to provide empty shells. They swap shells as they grow but also seem to swap them at other times (sometimes returning to their shell after it has been cleaned up by other critters or another hermit. They seem particularly interested in swapping shell when they are first put into an aquarium and seeing them change is an entertainment you should not miss. I have found it difficult to keep most snails when I keep hermits and usually have one or the other in a tank but not both (or not both after awhile). Some snails seem to fair better than others though and there is no harm in mixing them, just be aware that you may end up with only hermits.

I am not sure what a tiny flat crab is but at worst, you will be providing food for the hermits and increasing your bioload. At best you will be providing live food for your octo that will work on keeping your LR clean until it is eaten.

One word of caution about beach critters. The water around human activity is often not the best and scavengers are likely to contain poisonous pollution. I would prefer to quarantine the crabs for a week or two (I am not sure how long it takes to flush their systems, I usually keep oysters/clams in a tank for a week before offering them) before putting them in a tank unless you are sure the water is clean. You might post a general question to get the attention of one of our staff members or biologists for an idea on how long it takes to purge a small scavenger's system.

Unfortunately, rock will turn brown (as do bleached coals and just about everything else) with algaes. The best cleaners I have found are urchins but they are not a good idea for an octo tank. I keep multiple aquariums and will send in an urchin or two to clean up the rocks in an octo tank when the tank has no current cephalopod resident.

Most octos like to crawl more than swim so creating crawl space gives them more territory. I have the typical pile-o-rocks set up in all three tanks (rocks center stacked with open areas and dens in the back and sand around the sides and in front) but we are enlarging one octo tank and am thinking about trying something a little different. Depending on the species and individual octopus, some of your rocks may get rearranged but providing multiple denning areas (gaps in the back and caves) that are stable is probably the most important thought in how to arrange rock rather than sand to rock ratio. Equally important is to allow enough room to clean the glass without moving the rock stack (you will find this to be much more than you would think, 4" (10 cm) from the sides is the general minimum recommendation. I find it easiest to black out the back (some of my tanks have black acrylic, others I have added a black film to the outside) and only clean the sides and front. The new tank (very old tank but new to the breakfast room) has a side blacked out in addition to the black backing so I may put rock against the side in this one as well.