Nov 19, 2010
I am going to mainly keep cuttlefish to begin with, but eventually i want a octopus. I have a overflow box, and about 6 holes in the top of the tank excluding the large lid holes. What is the best way to octoproof this tank. THe water level is down aboutid say an inch from the top of the tank. It is not rimless. I will show pics of the holes i am concerned about also. I thought about also keeping an octopus shortly after things in the 75 get cycled and settled for alittle bit. That all depends on me making up my mind on what i want more/ availablility. From my understanding you can get an octopus at just about anytime you want, and you could be on a waiting list for Cuttlefish :sad: I am currently setting this tank up for Cuttles right now, but i always wanted both. So alternating is the option. Soon this will be the only tank i will have set up besides hopefully a biocube strictly for coral prop.. I might try to squeeze 1 cuttle in there or a dwarf octo though we will see :wink:!!! Also any segestions as to what species would be great? Its a 75 gallon long.. you can view pics here if you do not already know about it. http://www.tonmo.com/forums/showthread.php?22261-Tank-is-operational!!
I would like a species i will be able to see a decent amount if possible, and one i could interect with and give frozen food as a alternative food source. I was thinking Bimac? But i could be completly wrong. I have done more research since i joined the forum on Cuttlefish, rather than Octopus.



Staff member
Nov 20, 2002
Dallas Texas
I had holes for ventilation in the plastic cover of my octo tank. I octoproofed the cover by cutting a piece of plastic mesh an inch or two larger than the holes, and ducktaping the mesh to the top of the cover. It worked very well.



Certified Ceph Head For Life
Staff member
Sep 4, 2006
Gainesville, GA
Any hard surface square (acrylic, plastic, glass)1/2" or larger than the open holes can be easily attached with the Automotive trim tape (IMO, stick with the 3M brand). You could use a circle but the tape will go on a lot neater if it is square or the cover is opaque and you don't see the tape. Without a lot of effort it can be removed without leaving a residue, it looks better than duct tape, can be added when you need it with little effort and will prevent escape. The area around the pipe is not so simple. I think I would look for an oversized round sponge with a hole in the center, slice it about 3 inches long and thread the pipe though it. The diameter needs to be a tight fit on the diameter of the hole and keep it short enough not to be in the water.

I would add a hinge to your cover and a couple of acrylic hasp locks. There is some really inexpensive silicone hinge that holds up well and true acrylic piano hinge but both need flat surfaces at the joins. What I have done when my surfaces are not flat is to use the acrylic hasps as hinges. On all my tanks with the acrylic hasps, I attach both pieces with the afore mentioned tape. You will have to be sure that the light height won't be a problem if you decide to hinge the top. I get these from Tap Plastics. When I use them as hinges, I secure the two together with a zip tie. I have not found a perfectly sized pin to go where a lock is supposed to go. None of the rods they sell are quite the right size. A length of bamboo skewer works but it defeats the neat, clean look of the hasp.

Monty's scavenger tank top (scavenged from and old top and scraps) is an over use example of how we have used the hasps and silicone hinge

You are allowed to be a member of both the octopus and the cuttlefish forums :wink:. We don't fight and several people have kept both.


Haliphron Atlanticus
Sep 25, 2006
just to have another attachment method in mind as you think about how to secure your tank, remember that acrylic can be easily drilled, and you can easily use a tap to put threads inside the hole. Then you can use nylon bolts to securely hold things down, but still be able to remove them. I used this method to secure an acrylic top to the plastic top trim of my glass aquarium. When drilling acrylic, be sure to clamp a piece of scrap wood to the back, or the back of the hole could chip.

There was a news story a year or so ago about a bimac at a southern california public aquarium that pushed a piece of plumbing up and out of its tank, causing the pipe to pour water on the floor for a few hours instead of into the octopus tank, so secure your plumbing too. If you don't have a sump, be careful not to overly restrict fresh air flow to the surface of your tank, or you'll have low gas exchange (skimmers don't oxygenate water very well, so don't count on those).

I built a hinged top, but I didn't trust myself to always remember to latch it after I closed it, so I designed and built a simple latch that automatically latches whenever the lit is closed. You can see pictures of it HERE.

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