Tank selection

Discussion in 'Tank Talk' started by mercatoris, Apr 1, 2010.

  1. mercatoris

    mercatoris Pygmy Octopus Registered

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    Is it an ok idea to use a ready made setup like this for octopus mercatoris:
    http://www.redseamax.com/redseamax/250Temp/redseamax/Red_Sea_MAX_HP_130D.html
    Maybe with some mods to increase the amount of protein skimming or whatever is neccessary. It's possible to just get a 30 drilled and work from there, but I'm wondering if anyone thinks its a particularly bad idea to get something like what I linked to and use it as a tank for mercatoris. I don't want to cut corners but maybe it's smart to get a setup like this, economically and practically. I assume there would be mods needed but that may be easier than starting from scratch. I have seen people say there are problems with overheating on these small all in one tank setups but I assume the low level of lighting needed for a mercatoris might balance that out.
     
  2. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    That looks very promising. On major problem with the nanos has been the durability of the top (Nancy has replaced hers and we removed ours completely and added a glass top mod and new lighting - ours is almost 10 years old, Nancy's is only a year or two and the top was warranted - so I would look for reviews on this particular unit). The biggest concern would be the possibility for the octo(s) to get into the filter area. It says the height of the skimming overflow is adjustable and I would set it so that the water level is the lowest possible and consider putting a sponge or other type screen in the overflow chamber (it is a nice dark place). It may be high enough (far enough out of the water) that it does not attract the octo(s) but I don't think so. If you look at Sisty and Medusa's photos, you will see that they will reach up a couple of inches above the water line and there needs to be no exit routes within their reach (a 2"-3" top surround works well but would be difficult to add to this).

    Nancy added a stronger skimmer to her reef tank but if you do not put many corals (feeding issue) in the tank a small skimmer should be fine. I have a Skelter on my 15 gallon and my little guys live a full life span without issue (I DO do a major 5 gallon water change WEEKLY though).

    You will want to find a way to red light the aqaurium. High heat red vellum may work well if placed inside the light cover (I found mine on eBay but there was not a current listing to provide a link).

    I would also recommend keeping a pair of mercs rather than just one.
     
  3. mercatoris

    mercatoris Pygmy Octopus Registered

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    I would definitely hope to keep multiple mercs, maybe in such a small tank I could accomodate three, or is that too crowded? I have yet to test the reality of how hard it is to actually get multiple much less a single specimen, and that is a long way away, but the goal is a small group so there is a chance they'll breed and because I know they are supposed to be more active and interesting when they have company.
    The setup I linked to has what seems to be in and out plumbing connections for external filters and maybe I could add a sump and increase the capacity of the tank (so it could accomodate three mercs.) I don't know if a cube tank like that could house three or only two, I know they have pretty minimal space requirements and will get lost in big tanks but I don't know how it will actually play out with them crowded together in a 24" x 20" x 20" tank or whatever it is. I suppose get a pair and hope it's a male and female is the best you can hope for.
    So it would be difficult to octo proof this setup but it is not out of the question? Lowering the water level, and maybe creative use of sponges to block access to the filter? I like the look of the tank I linked to, it seems like a good deal but I guess I should make sure I know what it will take to make it really, truly octo proof. Thanks for the reply it's good to plan this kind of thing really thoroughly.
     
  4. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    I believe three will work in that tank (I raised 3 in a 45 and 2 in a 15 and felt the 45 was too large) with dilligent water changes and a rockwork set up that will give them separation (multiple dens on 3 sides recommended).

    When mercs are plentiful, getting 3 that have been living close together is often not a challenge (TONMO's Danthemarineman finds them in their live rock and will often have multiples in the spring, sometimes he will offer a price break for more than two).


    It is most likely that you will receive adults. Getting a sex mix is less the issue than obtaining a female (as adults they have likely already mated). They are very small for half their lives so they don't often show up in the trade until they are at least 5 months old and sexually mature (I did not even release mine to the tanks until 5 months, Medusa was not sexually mature but Sisturus was at this age).

    In spite of some of the things I have read, I have found little issue with octoproofing for the mercs. My 15 gallon hex tank has an open overflow that has never been a problem BUT the overflow is always lighted by the 24/7 red light (no nice dark attraction). For nocturnals, lighting any area that might be an undesired attraction may be one of the simpler ways of elmiinating the problem. The mercs do not seem to like being out of the water and the most I have seen with three generations of one family and three other individiuals is the exposure shown in the linked picture above. Unlike their briareus cousins, they are not strong enough to move a lid but they can get through small openings and built in sumps have been an issue with the nanos. If you can fabricate a 3" lip under the hood and protect the overflow, I don't think you would need to do more.
     
  5. mercatoris

    mercatoris Pygmy Octopus Registered

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    Are mercs seasonal? If I get a tank up and running in the next two weeks I'll still have at least 3 months before I can think about getting any. Are they year round but more likely to be a certain age during a certain season? This leads to tangential questions I have like what is their known range (how far north do they exist and what is their lowest tolerated temperature). And how plentiful are they in their habitat, that's a question I would like to know the answer too. Are they common on all Caribbean reefs or just Florida?
    In a tank that size (34 gallons minus live rock) would you recommend water changes of five gallons every five days? Maybe ten gallons a week is better but I wonder if that's not needed or harmful. It could be like changing 50% a week but maybe that's the right way to go about it.
     
  6. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    I have an odd theory on water changes that seems to work for the 8 (mantis), 15 (merc), 25 (mantis), 30 (anemone and clowns),45 (octo), 60 (octo), 65 (octo) and 145 (softy reef, misc) gallon tanks. I change out 5 gallons every 7 days (except for the pico as mentioned below and often the 145 gets an every other week wc), regardless of tank size (my additional water change exception is, I will do the same change twice a week if I notice odd behavior but that is rare except during senescence). My reasoning is that the amount is impactive in any of my tanks but smaller tanks deteriorate faster and have less air/CO2 exchange than larger ones and need a higher percentage change. My pico get a 98% change and I have no deaths even though I almost drain the tank weekly but I only keep a few oddball critters in the tank (It includes a tiny shrimp, crab, star and baby pencil urchins that have lived for over a year). Keep in mind that water temperature is critical when the percentage is high so my water stays in the room for an hour before it gets swapped. I have raised mercs from hatchling to 13 months (considered very old) in both the 15 and the 45 using this method. I DO have a cascading filter on the 15 and an air stone in the filter to aid Air/CO2 exchange (the 45 has a sump with an open water dump). The issue of releasing CO2 in a closed water environment is something to consider.

    I am not at all sure on the physical range for the merc. I do know they are found in South FL on both the Atlantic and Gulf sides, as far north as Tampa and as far south as Tavernier Key. Octopuses breed year round but there seems to be a greater abundance during the spring. The appearance of a larger number at that time my have more to do with them being bicatch than any real seasonal brooding. There is a possibility that water temperature may impact brooding and does impact hatching time so seasonality may still play a major role. Like many of the critters in the ocean, quantity seems to run in spurts. We have had more octos available the last two years than in years prior. This may be more because of demand and/or fishermen finding an outlet for bicatch in hard times than anything to do with counts in the wild. They appear to be abundant in the wild populations and are not an animal considered endangered but we don't count octos to the thought is antecdotal at best.

    One thing that does not get mentioned about water changes that I believe is a critial oversight. Changing the water is only PART of the procedure. Cleaning the bottom substrate should always be included as part of this maintenance. I try to stir my sand and simulaneously vacuum at the same location. The water in the tank should look much worse when you are done than when you started. I recommend doing waterchanges the day before visitors, not the same day :wink:
     
  7. mercatoris

    mercatoris Pygmy Octopus Registered

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    5 gallons a week at the same temperature sounds reasonable. In a puffer book I read that suffocation is a risk because of their high waste outputs in small tanks if you don't do a big water change weekly. Octopuses must be in the same category, potentially deadly conditions if you don't change the water. I don't know how much neglect it would take for that to happen but I don't want to test it.
    Stirring up the sand and getting all their leftover food out is important but you don't ever have problems with sand getting in the filter? I suppose if it were a problem there wouldn't be so many reef tanks with sand and powerful filters on them...
     
  8. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    The object of stirring it all up is to get the junk in the water column (direct siphoning just speeds up the process and does a better job IMO) to get it TO the filter (the sand settles down pretty quickly but the tiny stuff stays suspended for awhile.
     

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