FishBase Maximum Sizes- How accurate?

[Zionas]

I am curious as to how the maximum size on FishBase is determined. Is it the size of the largest specimen ever caught, expected size for pretty much more or less all specimens, or maybe the high end of average?

Some species also list a Standard Length and Common Length so maybe those are better measures of the size a fish will grow to?

For example it says Purple Tangs can get to 36cm (14.5"), Scopas to 16", Powder Blue to 14-15" also. If going by that all of them would need at least 8' (if not 10'), 300+ gallon tanks.

So for example like a fish that lists its maximum size on FishBase as 10" should we expect them to grow 10" or more in our systems?

Or maybe treat it more like human height where we have some very tall people but they're not the norm? Like you can have a 6 ft 5 male but most men fall between 5'7-6'0.

 

[Zionas]

The maximum size of some smaller Chrysiptera damsels like Azure and Yellow Tail Blue are listed as 2.75” / 7cm yet most people seem to have them not get much larger than 1.5”-2”.

For Ocellaris Clownfish it says they can get to 4.3” (11cm) which I am sure are referring to the females but does anyone have an Ocellaris female that big or close to that big?

I’m personally not quite sure about whether tank size does indeed limit fish size (leaning towards no) but it’s more a question of whether 90% of the time we should expect our fish to reach the maximum sizes listed online, especially more authoritative sources like FishBase?

BTW FishBase also says Flame Angels get to 6” but I’ve not heard of any getting to 6”.

 

[Timfish]

I see FishBase gives maximum length for Flame angels as Total Length or TM which is from the nose to the edge of the tail fin. Researchers sometimes will use SL, which is the length of a fish from it's nose to the base of the tail fin since there can be variations in the tail length. Three major factors that I see that could affect a fishes size are genotype, social structure and diet. With the damsels mentioned as an example, social structure would be the most likely variable noticed as they are sequential hermaphrodites and only older females will get close to the maximum recorded size. We can't identify genotyoes yest so it's impossible to say how big a factor that is and while we can monitor diet once we get a fish we don't know how old a fish is and how well it fed before we acquired it. I wouldn't expect any fish I get to reach maximum recorded size any more than I would expect any cat or dog I get to reach maximum size for thier respective species/bred.

 

[Zionas]

Thanks that’s really helpful. How big have your 20+ year old Tangs grown?

 

[Timfish]

That's actually hard to say with any accuracy. With refraction through glass or acrylic that will magnify I really need to place a ruler in the tank and get a full length picture of them in front of it which is a lot harder than it sounds since they are leary of anything new. But I would guess they are roughly 80% of maximum length

 

[Zionas]

I see.