52"x30"x30" - bigger fish for same

[mattsilvester]

Hi all,

Many of you will know me from the FO forum...... so this post is slightly unusual for me. I am planning a new tank which will be in the region of 52"x30"x30". An odd shaped / sized tank I know, but I saw one similar in size today and believe me when I say it is bigger than it sounds..... I would actually consider it similar to a stanrd 180..... furthermore I have seen tanks of this proportion in public aquariums and to be honest, bigger fish seem to be more at ease and natural in the wider / deeper proportions than they do in standard 180 configurations (they seem to move more in 3 dimensions rather than just to and fro).

Anyway - notwithstanding the above, the fact remains that 52" long, is not long enough for big fish like naso tangs and queen angels..... lets not kid ourselves...... so I am left wondering, what bigger fish (reef safe / semi reef safe) would you consider as options for this tank. Note I say "bigger" and BIG....

I don't mean a stocking plan..... so you can list incompatible species...... I'm just looking for ideas for this unconventional size / shape tank.

The tank will be visible three sides - room divider type of thing, with one 30"x30" panel to the wall..... so aquascaping will allow for swimming all the way around the 3 sides.

Many thanks in advance.

[JHemdal]

Matt,

The two measurements you want to work with is length plus width of the tank, open water only. If you try to use LxWxH, you end up comparing the length of the fish to the volume of the tank, and it won't work.
Here is my first attempt at a method for quantifying swimming room for fish. I sent it to Practical Fish Keeping in England, so it didn't get much exposure outside of Great Britain, but I noticed that they put it up on their web site a short while back:

http://www.practicalfishkeeping.co.uk/content.php?sid=3048

I've since revised the procedure, refined the numbers a bit, and the new version will be coming out next year in Aquarium Fish International, so it should get broader distribution then. Is this method perfect? Of course not, but it is better than just guessing. One caveat is that it only considers the swimming roon needs of a single fish, so multiple fish in a tank still need to be dealt with "off the cuff". I've applied it to fish from 1" long zebra danios to the whale sharks in the Ocean Voyager tank at the Atlanta Aquarium, and it seems to work pretty well.

Jay

[mattsilvester]

Matt,

The two measurements you want to work with is length plus width of the tank, open water only. If you try to use LxWxH, you end up comparing the length of the fish to the volume of the tank, and it won't work.
Here is my first attempt at a method for quantifying swimming room for fish. I sent it to Practical Fish Keeping in England, so it didn't get much exposure outside of Great Britain, but I noticed that they put it up on their web site a short while back:

http://www.practicalfishkeeping.co.uk/content.php?sid=3048

I've since revised the procedure, refined the numbers a bit, and the new version will be coming out next year in Aquarium Fish International, so it should get broader distribution then. Is this method perfect? Of course not, but it is better than just guessing. One caveat is that it only considers the swimming roon needs of a single fish, so multiple fish in a tank still need to be dealt with "off the cuff". I've applied it to fish from 1" long zebra danios to the whale sharks in the Ocean Voyager tank at the Atlanta Aquarium, and it seems to work pretty well.

Jay

Jay,

Thank you for your reply. It is extremely helpful, and great to see someone apply some degree of science to a topic which is mostly governed by conjecture and baseless opinion. I have long been an advocate of apply the rule of thumb that a tank should be 6-8 times the length of the expected captive adult size of the fish..... and at least twice as wide as that length..... and applying the same logic as you when determining which end of the 6-8 scale it should be i.e. sedentry / maneuverable / cruisers. And of course, as you have pointed out - rules of thumb are just that, and a degree of discretion needs to be applied..... for example not all tangs are eaqual.... such as a naso tang and a yellow tang. Please see my signature:

Rules are for the obedience of fools and the guidance of wise men."

"Nemo mortalium omnibus horis sapit" - no man is at all times wise.

Your forumula makes much more sense to me..... for example, a 4x4x2 square based tank is equal in volume to a 8x2x2..... but some people would say that you cannot keep a larger fish in the 4x4x2 because its not long enough..... a weighting factor needs to be applied...... and I think your formula works well.

One thing perhaps you could offer further guidance / explanation on is the "open water" aspect. For example, in my proposed tank of 54"x30"x30", a couple of scenarios could exist.

Scenario 1: I keep the aquascaping low and flat, so it is no higher than 12" into the water column, letting 18" above it..... does that mean I can apply:
52+30 = 80
sedentry: 80/(3.5-5) = 16-23 adjusted adult size
maneuverable: 80/(5-7) = 12-16 adjusted adult size
cruisers: 80/(6-8) = 10-14 adjusted adult size

Scenario 2: I design a very open aquascape, where fish can swim in, around, through, and under the rockwork - relatively unrestricted..... still allowing say 9" front and back of a long narrow central island bommie....
So I would say 52" + (9" + 9") = 70"
sedentry: 70/(3.5-5) = 14-20 adjusted adult size
maneuverable: 70/(5-7) = 10-14 adjusted adult size
cruisers: 70/(6-8) = 9-12 adjusted adult size

Scenario 3: Less effective aquascaping, essentially reducing the open width by 50%:
52+15 = 67 with corresponding sizes of-
sedentry: 13-19
maneuverable: 10-13
cruisers: 8-11

So if we are to be conservative about it (based on preferred minimums of 1:5 / 1:7 / 1:8) then the max (adjusted) adult sized fish should be:
sedentry: 13 (say a volitans @ 15"x0.66 = 9.9")
maneuverable: 10 (say an emporer angel @ 15.7"x0.66 = 10.4")
cruisers: 8 (say hippo tang @ 12.2"x0.66= 8")

My own personal rule of thumb, which has stood to me well over the years of 6-8 times the length would equate to:
54" / 6 = 9" for sedentry - maneuverable
54" / 8 = 7" for maneuverable - cruisers
This would be slightly more conservative than your formula, but the similarity is more than coincidence, in my opinion, ad it validates yours and mine formula..... as such (albeit yours more scientific and ocmplex :thumbsup:)

Where hte nay-sayers will jump on board here is they will contest that an emporer angel, will grow larger than 10.4" and is more of a cruiser than a "maneuverable" species...... to which it could be counter argued that if we use "scenario 2" above for aquascaping and put the fish into lower end of the cruiser at 1:6 (because it cannot be argued that an emporer is as much a cruiser as say a naso), then we get 12"..... and there are not many captive grown (from juv.) emporers more than 12" in captivity....... so it still holds water.

I think this is an extremely interesting discussion. I am generally very conservative in my stocking plans, and for the record would not personally keep an emporer in my proposed tank..... at least not an adult one..... but it certainly makes more sense to me than arbitrary and guestimated rules. It would be very interesting to make a drop-down-menu spread sheet in MS excel. Of course, discretion and sensibility needs to be applied..... particualrly as you noted, when interactions with tank mates is considered for example..... and certain fish species like passer angels for example need special treatment due to abnormally higher aggression etc.

I would be extremely interested to hear back from you, to see if I have interpreted your formula correctly.

Thanks for sharing!

[palmer373]

Matt,

The two measurements you want to work with is length plus width of the tank, open water only. If you try to use LxWxH, you end up comparing the length of the fish to the volume of the tank, and it won't work.
Here is my first attempt at a method for quantifying swimming room for fish. I sent it to Practical Fish Keeping in England, so it didn't get much exposure outside of Great Britain, but I noticed that they put it up on their web site a short while back:

http://www.practicalfishkeeping.co.uk/content.php?sid=3048

I've since revised the procedure, refined the numbers a bit, and the new version will be coming out next year in Aquarium Fish International, so it should get broader distribution then. Is this method perfect? Of course not, but it is better than just guessing. One caveat is that it only considers the swimming roon needs of a single fish, so multiple fish in a tank still need to be dealt with "off the cuff". I've applied it to fish from 1" long zebra danios to the whale sharks in the Ocean Voyager tank at the Atlanta Aquarium, and it seems to work pretty well.

Jay

wow thanks a lot! ill have to re-read that article to understand it 100% but itll be useful.

[dohc97]

very interesting formula, since you posted this and i know i can expect a straight, honest answer. What are your thoughts on keeping an angelfish(false personifer) in a tank that is 6 feet long-20-22" depth but only about 16" tall. I know everyone keeps throwing me high gallon tanks as proper but i dont have the floors for such heavy tanks. My main concern is swimming room, am i wrong to think this tank would be ok?

[JHemdal]

dohc97,

That brings up a good point: for my work, I use "length" as the open water length of the tank from left to right. For "width", I use the same open water distance from front to back. For "depth", I use the water depth from top to bottom. Some people (especially in Europe) tend to interchange "depth" and "width" - so that can cause issues.
From my experience, minimum tank DEPTH is not a real issue. I've never seen an aquarium that was too small for a given fish in regards to its depth. In fact, public aquariums will frequently use very shallow tanks to hold sharks during quarantine - giving a final volume that seems too small, but the fish are fine. The exhibit tank that the fish will eventually be placed in may be much deeper, but that is for esthetic consideration. For that reason, I took tank depth out of the equation - length + width works much better.
Just ball parking it here (I didn't actually run the fish through the equation), I see no problem keeping an adult false personifer in a tank with the footprint that you mentioned.

Jay

[JHemdal]

Hi Matt,

I fully agree that there is no problem at all in being more conservative than the caluclations that I presented will allow - you simply cannot go wrong by giving a fish MORE room to swim (grin). My attempt here, was to give people a MINIMUM tank size, below which, the fish would begin to show some signs of "artifacts of captivity" - rubbed snouts, deformed fins, and of course, a shorter than expected life span. If these artifacts are NOT seen, is there then a problem? I would say there is not...so that is the minimum tank size that I factored in to the equation.

To address part of your question - I have not been a subscriber to the idea that tank LENGTH alone is the metric to be used in deteriming fish swimming room. I feel that this is actually a function of length and width (with depth being less important, as I mentioned in my previous post).

My call for the tank measurements being taken as "open swimming room" is a vital consideration for some home aquariums that have massive amounts of LR and other obstructions to swimming room. I've heard from too many people say that they are keeping a fish of "X" length in a 180 gallon tank - but never mention that 80% of that tank was being obstructed by coral and LR...

Jay

[dohc97]

dohc97,

That brings up a good point: for my work, I use "length" as the open water length of the tank from left to right. For "width", I use the same open water distance from front to back. For "depth", I use the water depth from top to bottom. Some people (especially in Europe) tend to interchange "depth" and "width" - so that can cause issues.
From my experience, minimum tank DEPTH is not a real issue. I've never seen an aquarium that was too small for a given fish in regards to its depth. In fact, public aquariums will frequently use very shallow tanks to hold sharks during quarantine - giving a final volume that seems too small, but the fish are fine. The exhibit tank that the fish will eventually be placed in may be much deeper, but that is for esthetic consideration. For that reason, I took tank depth out of the equation - length + width works much better.
Just ball parking it here (I didn't actually run the fish through the equation), I see no problem keeping an adult false personifer in a tank with the footprint that you mentioned.

Jay

figures that the day i choose to use depth is the day i get a professional to correct back to what i have always called width. I hear so many people refer to it as depth that i thought i would start using it :spin2:

enough of my hijacking, thank you for the help