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Where can I get as much info on Bimacs as possible?

Blake

Hatchling
Registered
Joined
Jan 11, 2018
Messages
3
Location
California
Hey guys, I'm new to this (I've been secretly stocking these threads as a nonmember for months until I finally decided to join.) I'm just wondering what the top suggested books (or other sources) with all the info I need on keeping a Bimac are. I basically have everything I need and feel fairly confident in my understanding and my set up, but I have lots of little unanswered questions. Any info helps! Thanks in advance!

-Blake
 
Thanks for joining! You've come to the right place. We have some quality articles here, and many classic threads on bimacs. They are not as prevalent as they once were.

@Nancy and @corw314 both have some great experiences to share w/ bimacs. @DWhatley, you've had so many octo species... which journals would you recommend?
 
Thanks for joining! You've come to the right place. We have some quality articles here, and many classic threads on bimacs. They are not as prevalent as they once were.

@Nancy and @corw314 both have some great experiences to share w/ bimacs. @DWhatley, you've had so many octo species... which journals would you recommend?

Hey, thank you! I have noticed many people say that they are difficult to get ahold of nowadays. I do have a California fishing license and I've actually seen a few of them around in tidepools and such. I've been wanting to make a kind of "California themed tank" for a while now and a Bimac is at the top of my list. It's such an interesting animal. Anyway, most of my questions are small specific questions. I have a Herbie overflow draining system and I'm wondering if I just need to put mesh over the emergency drain pipe only since I wouldn't think it would matter if the octo was climbing into the overflow, right? Just another hiding spot for him to hang out in I would assume. Or, I've noticed most people use a wet/dry filtration system, but my sump has a refugium instead. Is that something I should change? Most of my questions are along those lines and I can't seem to find threads that answer questions that are that specific haha. Hoping to find some kind of source with lots of info on these guys so I don't have to bother everyone with every little question I have. Thanks again in advance for any responses!
 
My apologies for the delay but I just noticed your post.

I have a Herbie overflow draining system and I'm wondering if I just need to put mesh over the emergency drain pipe only since I wouldn't think it would matter if the octo was climbing into the overflow, right?
Depending upon the size of the animal, you will need to cover both outlets in some way. From tie images I found of a "Herbie overflow" one of the two overflows is equipped with a filter. A second filter on the emergency overflow would be needed to keep the animal out of the sump. If the animal is very young, it would be wise to keep it out of the weir entirely with sponges or screening until it is too large to exit through the slots in the filter.

I've noticed most people use a wet/dry filtration system, but my sump has a refugium instead. Is that something I should change?
Refugium sump is fine but the addition of a skimmer is highly recommended for both ink and protein removal.
 
You are following a similar path to what I did, but I did it back in 2006-2011. I used a wet/dry system with a floss pre-filter that I checked daily, an oversized skimmer and a deep sand bed in the tank (to try to lower nitrates). It worked great for the octopus, but I had trouble keeping the PH and the nitrates down. The octopus, sea stars, and anemone were fine (tide pool animals are very robust about such things) but the corinactus (strawberry anemone) never really thrived (PH? too much light?).
I would add chemical filtration if I did it again, and larger tank (mine was a 65 gal I modified to have the wet/dry chamber inside the tank (keep the cold things together) so about 50 gallons for the bimac. I'd also consider a nitrate reactor or huge external deep sand bed to reduce nitrates faster to allow for more time between water changes.
For me the whole design of the system starts with the need to keep the water temp within the natural range (55 F in winter, 62 F in summer). Colder is better, so a constant 55-59 is the thing to aim for. I could get two years of life out of a babyish (2-3 inch) bimac with cold water and minimal feeding.
I'll address your specific questions in my next reply, but feel free to hit me with all of your specific questions. I'm near San Diego, so if you are too, I can arrange to show you my setup.
 
I have a Herbie overflow draining system and I'm wondering if I just need to put mesh over the emergency drain pipe only since I wouldn't think it would matter if the octo was climbing into the overflow, right? Just another hiding spot for him to hang out in I would assume.
Bimacs are clever, curious, strong, bored, and would much rather get out than "hang out". It's going to push and/or pull on whatever it can (hard) and try to squeeze through any crack or opening, so think through how you are going to secure the top, and the filtration system, against such a foe.

I've noticed most people use a wet/dry filtration system, but my sump has a refugium instead. Is that something I should change?
A reef system is dainty and spends all day converting light into a little food. Think of an octopus tank more like a heavily stocked fish-only tank (or a rugby team at a pizza place after a scrum). The waste comes in two main forms and both are big dumps rather than slow trickles. Shreds of uneaten food get into the water on feeding day, and a lot of octo poop comes at point in time after that. Your filtration system needs to try to get as much junk as possible out of the water as it can, BEFORE that junk needs to be broken down and processed by your colony of nitrofying bacteria. A physical filter (floss?) that gets cleaned or discarded often is great at getting the table scraps out of the tank (assuming you have a lot of flow to get those chunks up off the bottom and into the filter). An oversized protein skimmer also gets junk out before it needs to be broken down further.
In a cold water system the bacteria in your bio filter slow way down, so you need a lot of them (think oversized), and you need to limit feeding.
A refugium can be good at exporting nitrogen if you grow and harvest a lot of plants from it, but it works toward the end of the process. Even if it has a team of critters to eat scraps (a good thing) it's still better to get the scraps out before they need to be broken down. I'd be suspicious that a refugium would be a good thing (especially if it has a deep sand bed) but wouldn't be sufficient by itself.
Brittle stars are great in the octo tank. The bimac will leave them alone unless it's starving, and they will come out at night and look for detritus.

And some advice you probably wouldn't think to ask for: Even though they live togtether in the wild, avoid putting cowries in a bimac tank. Eventually the bimac will try to eat the cowrie, and as a defense it will produce a literally unbelieveable volume of slime so thick that it will clog your overflow like jello.
 
The easiest time of year to catch a bimac is Dec-Jan, back when he started this thread (super low tides during daylight hours) so I suspect he was ready to pull the trigger. If he did, this might be the time he's generated the most questions. If so I hope he comes back and asks. This site helped me a lot when I got started.
 
I'm just glad to see you back! However, the time warp comment was because it was a Dec '17 - Jan '18 post. The info is timeless and others looking will find it.
 

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