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New to Cephs: Just got a Mercatoris

Joined
Oct 1, 2020
Messages
11
Hi folks. My little guy is sitting in a fish trap in my main tank with hiding places and he had a crab for a midnight snack on his first night home. I am setting up a tank for him but he will stay in the fish trap until then. I click on the Mercatoris tag on this forum and only found 4 threads so I am reaching out to learn as much as I can. Please help me with links to credible resources to read and your expertise would be most appreciated.

Habitat:
I'll be setting up a tank with a submersible filter and a lid. will make sure the water level is at least 1 inch below the lid - would he still crawl out? The lid has gaps on all sides so I'll have to work on that before I put him in there.
Recommendation for filters? What about a circulation pump/powerhead? Is he going to go an kill himself?
I don't intend to have corals in here, maybe common mushrooms and zoas, but I am intending to keep macro algae so the light has to be bright enough - do they tend to hide when there is a bright light on the tank? I will have hidey spots a-plenty.
Does he need sand?

Food:
He had a crab. He's tiny so how often do I feed him? Will he eat a live mussel or clam?
I am not sure if I can get live crabs all the time. I know he's not strong enough to open their shell so I will be helping. I hope he likes frozen but time will tell. (I'll wave it on a bamboo skewer to entice)

I'm sure I will have a ton more questions - thank you for your help.
IMG_20201001_122244.jpg
IMG_20201001_121335.jpg
 
Joined
Oct 1, 2020
Messages
11
welcome to TONMO, @squishy2020 -- thanks for joining and sharing!


Hmm, that's odd, I count 22 threads (and I am sure there more as all our content is tagged yet. Try this link: mercatoris
Thank you, I am going through them, was hoping for a comprehensive guide - but I guess I will read through journals. One of the links offered details on how ot set up a tank which had some info but it was mostly geared towards explaining the nitrogen cycle and types of filtration available, not really this is the most common filtration used for an octo tank and why.

He is currently in a fish trap in my main tank and I'll leave him there till his tank is ready. I'm still trying to figure out what to give him for live food - please suggest.

Thank you
 

Nancy

Titanites
Staff member
Moderator
Joined
Nov 20, 2002
Messages
5,772
Your little guy will eat crabs and shrimp (even good quality thawed frozen shrimp).
He will also eat clams and mussels, but shrimp and crabs are preferred. Be sure to clean up any remnants.

He will not eat bait worms.
Nancy
 

AvianMan

Hatchling
Registered
Joined
Oct 27, 2020
Messages
2
Hi! I have a mercatoris. He eats grass shrimp (when he can catch them) and will also eat frozen (thawed) krill without hesitation.
 
Joined
Oct 1, 2020
Messages
11
Hi everyone. Ragnar Octavius Inksalot (Inky) has been living with me a month now. He's magnificent. 100% nocturnal and we have not become friends yet. He's quite a diva - throws his trash at me! I have a night vision camera on him so I catch some shenanigans every now and then. I also have a red light on his tank 24/7 with other ambient light filtering in during the day.

After Inky was done with his hermit crab snacks (he likes to hold on to empty shells as a security blanket, I got him fiddler crabs which I throw in the tank one at a time every 3 days or so. He's really tiny and the crabs are a lot for a little dude, at least I think so.

Inky2.jpg


I am planning on adding sand and a barnacle to his tank (he has live rock right now) but the barnacle and sand in my reef is nasty so I'll have to get new ones.

I have some questions:
-Any thoughts on how to get him to come out to play during the night?
-Is Feeding one crab about every 3 days sound right? too much? too little?
-How often should water changes be done?
-His tank doesn't go lower than 78 even though my apartment is a lot cooler, it's the huge filter that is in the tank, any suggestions on how to cool the tank down, it's got a lid so it holds the heat.

I have seen daylight videos and pictures of Mercatoris and I'm wondering how those animals were acclimated to the light and how long it took.

Inky doesn't like to play either, I've left a crab in a trap, some toys, he hasn't touched them.
 

adlysia

Pygmy Octopus
Registered
Joined
Aug 25, 2019
Messages
7
Hi everyone. Ragnar Octavius Inksalot (Inky) has been living with me a month now. He's magnificent. 100% nocturnal and we have not become friends yet. He's quite a diva - throws his trash at me! I have a night vision camera on him so I catch some shenanigans every now and then. I also have a red light on his tank 24/7 with other ambient light filtering in during the day.

After Inky was done with his hermit crab snacks (he likes to hold on to empty shells as a security blanket, I got him fiddler crabs which I throw in the tank one at a time every 3 days or so. He's really tiny and the crabs are a lot for a little dude, at least I think so.

View attachment 73278

I am planning on adding sand and a barnacle to his tank (he has live rock right now) but the barnacle and sand in my reef is nasty so I'll have to get new ones.

I have some questions:
-Any thoughts on how to get him to come out to play during the night?
-Is Feeding one crab about every 3 days sound right? too much? too little?
-How often should water changes be done?
-His tank doesn't go lower than 78 even though my apartment is a lot cooler, it's the huge filter that is in the tank, any suggestions on how to cool the tank down, it's got a lid so it holds the heat.

I have seen daylight videos and pictures of Mercatoris and I'm wondering how those animals were acclimated to the light and how long it took.

Inky doesn't like to play either, I've left a crab in a trap, some toys, he hasn't touched them.
very cute! Is Inky a baby? I've found (with other species) that the babies are more timid and less willing to play... maybe you could start with putting more objects in the tank-- empty shells, dead coral, other potential hiding spots, etc. for Inky to explore and see if he/she will slowly start to come out during the day! :smile:
 
Joined
Oct 1, 2020
Messages
11
very cute! Is Inky a baby? I've found (with other species) that the babies are more timid and less willing to play... maybe you could start with putting more objects in the tank-- empty shells, dead coral, other potential hiding spots, etc. for Inky to explore and see if he/she will slowly start to come out during the day! :smile:
Thank you I will try that. I am not sure how old he is.
 

pkilian

Wonderpus
Staff member
Moderator
Joined
Jul 31, 2019
Messages
178
I have some questions:
-Any thoughts on how to get him to come out to play during the night?
-Is Feeding one crab about every 3 days sound right? too much? too little?
-How often should water changes be done?
-His tank doesn't go lower than 78 even though my apartment is a lot cooler, it's the huge filter that is in the tank, any suggestions on how to cool the tank down, it's got a lid so it holds the heat.
1- One way you may be able to encourage some more early morning or late night activity is to shift the light cycle of the animal slightly. This would require you to get a daytime light or adjust the light cycle on your red light. You can do this by having the red light turn off at night (maybe between midnight and 6am), leaving it set that way for a week or two, and then adjusting it by 15 or 30 minutes every day or two in order to shift their "night time" to be earlier in the evening. After a week or two of adjustment their red light could be off between 8pm and 2am, which might allow you to see some more activity around 8-10pm.

Additionally, if you time your feeds you can start to shift your feeding schedule to the time that you want your animal to be most active in the tank. Start feeding at midnight and then as you shift the light timer also shift the feeding time to make it earlier in the day. After a few weeks you will be feeding around 6-8pm and your octopus will likely expect food at this time, especially if you are feeding every day or every other day. Ill touch on this point below.

As an aside- why do you have the red light running all night? That could be contributing to your increased water temp.

2- One crab every 3 days might be a bit light on feeds, but it really depends on how large the crab is and how active the animal is. With an octopus, you don't need to worry about over feeding it from an animal health perspective. They wont get fat and aren't susceptible to things like fatty liver disease. They can't overeat and will just leave food behind or ignore the crabs if they aren't hungry. You could try feeding every other day while paying close attention to how long the crabs stay alive in the tank. If you routinely see the crab be eaten soon after it was added to the tank, you could try to increase the feeding frequency further. I would suggest trying to feed every other day at first, and if you regularly see the crabs alive in the tank for long periods of time (if one is still alive the next day after feeding) then you know that you don't need to be feeding every other day and you can go back to 1 crab/3 days. The most important thing to keep in mind while increasing feeding frequency is to ensure that the octopus is actually eating the crabs you put in, and that the crabs aren't staying alive to bother the octopus. A more regular feeding schedule can also help you encourage your octopus to be active around specific times of day, when they expect to be fed.

3- I would recommend routine water changes every week, and maybe additional water changes on top of that if you start to see your nitrogen levels rising. 10% volume/week is pretty standard for most aquariums, but again- this depends on your animal, the water quality parameters, and how well established your system is. You check your water chems every week or every few days right? If you are going to try increasing the feeding frequency to encourage some more activity around specific times of day, you will need to also increase your water testing frequency. Make sure to remove the leftover crab shells soon after they are eaten (I wouldn't leave them longer than a day if possible). They can wreak havoc on your water quality parameters. Crabs are nasty.

4- what temperature would you like your tank at? I can make a few suggestions. What about the filter do you think heats up the tank water? Is there a heater inside the filter unit that you can control?

Lastly, when it comes to toys in the tank- some octopuses (especially young ones or shy ones) just aren't that interested in playing with toys. There aren't any pool toys or rubix cubes in their natural habitat, and often the best way to give your animal some enrichment is to swap up the aqua scaping in the tank. This will give your animal new places to explore and find dens to build- and you will often get much more engagement out of swapping the rocks around than you will by adding a jar or a kids pool toy. Just be sure to move slowly and not spook your animal when you are working in the tank!
 

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