Mastacembelus dayi in a 75 gallon aquarium?

[BullTerrierChild9 29]

I was given information that my LFS ordered a Black Spotted Eel (Mastacembelus dayi) set to arrive tomorrow. This is ironically a fish that I have wanted to own for quite a while, but I want to make sure that it can fit in a 75-gallon aquarium due to it's large adult size. Judging by their body shape and activity level, I believe I should be ok, but I just wanted to make sure. My tank has plenty of hiding spaces, 2 tight fitting lids, and the only bottom dwellers pack themselves mostly in one cave (their choice, I have multiple) and my middle column dwellers are all slow-moving S.A. cichlids.

I have looked online. One source stated 55 gallons and another stated 90:

Aqua Imports Link
Tropical Fish Keeping Link


Thank you!

 

[MattW29 145]

@Boundava ?

 

[anewbie1]

I was given information that my LFS ordered a Black Spotted Eel (Mastacembelus dayi) set to arrive tomorrow. This is ironically a fish that I have wanted to own for quite a while, but I want to make sure that it can fit in a 75-gallon aquarium due to it's large adult size. Judging by their body shape and activity level, I believe I should be ok, but I just wanted to make sure. My tank has plenty of hiding spaces, 2 tight fitting lids, and the only bottom dwellers pack themselves mostly in one cave (their choice, I have multiple) and my middle column dwellers are all slow-moving S.A. cichlids.

I have looked online. One source stated 55 gallons and another stated 90:

Aqua Imports Link
Tropical Fish Keeping Link


Thank you!

The 90 and 75 have the same dimension but the 90 is taller; the 55 is a lot narrower. What i am reading is as an adult it will need a larger aquarium 6 foot min and 8+ better. Adults can get close to 20 inches and while it is not a fixed linear fish like oscar or severum it is a bit active at night.

I have not owned one nor have i considered owning one so this is just after 10 minutes of reading about them but my guess is as an adult you really want 8 foot long and 18 to 2 feet wide. However as a young fish 75 is fine. Unfortunately they grow fairly fast - so something to consider....

 

[BullTerrierChild9 29]

The 90 and 75 have the same dimension but the 90 is taller; the 55 is a lot narrower. What i am reading is as an adult it will need a larger aquarium 6 foot min and 8+ better. Adults can get close to 20 inches and while it is not a fixed linear fish like oscar or severum it is a bit active at night.

I have not owned one nor have i considered owning one so this is just after 10 minutes of reading about them but my guess is as an adult you really want 8 foot long and 18 to 2 feet wide. However as a young fish 75 is fine. Unfortunately they grow fairly fast - so something to consider....

Thank you! I'll take this into heavy consideration. There sadly seems to be little information on them ...

 

[GaryE29 144]

When I can't get a lot of info, I have a formula I use. I look up the absolute maximum size of an adult of the species, then I multiply it by eight. That gives me the necessary front glass. Gallons don't matter for behaviour.

It's a movement calculation. It doesn't take bioload into consideration. One of the problems with gathering online info on large fish is the monster fish hobby generally kills its fish long before they reach their potential. Too small tanks are killers, and monster fishkeepers, like all of us, tend to conveniently disregard the needs of the fish and write like they don't. If you're one of the skilled ones (there are many) then you'll be one with tons of space and resources for those big fish.

 

[BullTerrierChild9 29]

When I can't get a lot of info, I have a formula I use. I look up the absolute maximum size of an adult of the species, then I multiply it by eight. That gives me the necessary front glass. Gallons don't matter for behaviour.

It's a movement calculation. It doesn't take bioload into consideration. One of the problems with gathering online info on large fish is the monster fish hobby generally kills its fish long before they reach their potential. Too small tanks are killers, and monster fishkeepers, like all of us, tend to conveniently disregard the needs of the fish and write like they don't. If you're one of the skilled ones (there are many) then you'll be one with tons of space and resources for those big fish.

Thank you! I am leaning towards no.

 

[Boundava7]

@Boundava ?

So I have one bought as juvi around 8" and is growing quite well, though not as wide as my galaxy eel Nebula, s/he is growing at a rate to meet her 18-20" length in the near future. They are both in my 125.

I would think at least 120 for an eel of that size as mine is pretty active and is all over the 125 gallon tank, especially when s/he sees us (=feeding time, though it may not be). Currently feed cut up shrimp, it never showed interest in worms but likes jumbo bloodworms too. It knows a hand in the tank means food so it will grab shrimp bits from us (as will Nebula, my m. alboguttatus).

My m. alboguttatus has similar care requirements to the m. dayii but I could not see her in a 90 gallon, she is a chunky 18" right now.
m. Dayi

Nebula

They are fast growing so I would get something now to fit adult size.


What are you keeping with the eel? It may predate on smaller fish at night when they are sleeping as my unicolor would eat any fish small enough to fit in its mouth.

Sorry for the late response, work has been something today.

 

[BullTerrierChild9 29]

So I have one bought as juvi around 8" and is growing quite well, though not as wide as my galaxy eel Nebula, s/he is growing at a rate to meet her 18-20" length in the near future. They are both in my 125.

I would think at least 120 for an eel of that size as mine is pretty active and is all over the 125 gallon tank, especially when s/he sees us (=feeding time, though it may not be). Currently feed cut up shrimp, it never showed interest in worms but likes jumbo bloodworms too. It knows a hand in the tank means food so it will grab shrimp bits from us (as will Nebula, my m. alboguttatus).

My m. alboguttatus has similar care requirements to the m. dayii but I could not see her in a 90 gallon, she is a chunky 18" right now.
m. Dayi
View attachment 385002
Nebula
View attachment 385003
They are fast growing so I would get something now to fit adult size.


What are you keeping with the eel? It may predate on smaller fish at night when they are sleeping as my unicolor would eat any fish small enough to fit in its mouth.

Sorry for the late response, work has been something today.

Thank you!
I keep larger fish in my 75 gallon aquarium (mainly cichlids), so I don’t think anything would be eaten.

I went to look at it today (I don’t own it), it seems to already be in the 14-15 inch size in length and is surprisingly slimmer than I thought. It was very shy and curled up in the decorations. My tank has 3 caves, one of which none of my fish use (except for a 5 inch Raphael Catfish that stays on one “branch” like side, away from the main area).

Attached is a photo of the eel. I’m still on the fence but my ultimate goal is to provide adequate space, and I will not buy it if I can’t do so.

 

[Boundava7]

Awww, look at that face...
What is she eating?

 

[BullTerrierChild9 29]

Awww, look at that face...
What is she eating?

Oh-My fault! I don't own the eel (yet?)!
Since I only have a 75 gallon, I am still on the fence about whether it would work...
I have heard some yes's and some no's, but I held off on purchase for today, though I would love to own her!

 

[Boundava7]

Yeah, you mentioned she was slim so if you know the owners/store I would ask what s/he is eating and how often. I think the 75 is too small for a permanent home.

 

[BullTerrierChild9 29]

Yeah, you mentioned she was slim so if you know the owners/store I would ask what s/he is eating and how often. I think the 75 is too small for a permanent home.

Thank you! I'm not going to buy it but definitely a great consideration for if I ever get a 125! I believe that it is a fine weight (Slimmer as in compared to other "eels"), but I will ask if possible next time. It arrived last week, as well.