Polypterus;1038791; said:
I differ all comments on Cubans directly to Solomon as I have not personally kept this species.
Tropicals are just as mentioned.. 2 1/2 to 3 foot with the potential to reach a larger size of around 4 foot. These fish 'plateau' out around 14 to 16 inches and then grow quite slow from there with average care..Feeding them heavier or not putting them through an annual cool down cycle will result in a larger fish initially but they still seem to slow down a lot around the 16 inch range for a first year fish.
definitely agree on the assessment of the tropicals...richard and i have kept them in varying conditions (especially between the two of us, and amongst the fish in our care), and they all seem to plateau around the same sizes. in fact, fish that were brought in initially, from that "first" order back in 2005 are around 15-18" from what i have seen of people who still have theirs, or ones in personal collection as well as richard's.
i have high suspicions as to whether these fish would reach even 3' in captivity (as opposed to broodstock which are available at 3' size, and some other specimens which were possibly grown out in much larger enclosures), but only time would tell. the jury is still out and polypterus and i have many in-depth convos about gar growth in captivity...good examples of this are the rare finds of any shortnoses at 33", Floridas at 54", or longnoses over even 3' when it comes to captive raised fishes. even gator gars don't seem to be clearing much over 7' in public aquaria.
as for the Cubans, this is another fish which we discuss quite frequently. the fish that i have (or have kept in the past) are about 4 years old now, and still about 18" give or take. they are quite thick and definitely healthy, but they are growing quite slowly. they were brought in in 2004 at about 11-12"...so we're looking at 6" of growth over around 3 years.
in our discussions we have suspicions about the supposed 72" wild max of this fish, but it's also likely that the (probably) aquacultured specimens will not grow as large...there are also several other parameters to take into account with the Cubans, as they are by far the most challenging gar species i have kept (and richard can attest to this as he's been in close contact during the trials of keeping this species).
both great species, and seem to be easily kept in a 3' wide tank for quite some time...since these fish live for a long time, it's hard to say how long they can stay in this sized enclosure, but until we get evidence otherwise, we'll continue to advise people based on our current experiences. hope that helps, and feel free to ask other questions!--
--solomon