Looking through some notes, I found this:
I forgot to mention that Picard’s ready room bubble aquarium (both 24" and 36") where made by a company called AquaPlex in Hayward, Ca.
Makers of TruVu tanks and filters.
I worked there for almost 8 years
Pretty sure the larger one was used in the series, could be wrong on that since I haven’t watched the show in ages.
The large one was used in the movie Generations. (Trek Core has 3 pix of it empty after the D crashes)
While we didn’t have a bubble tank in our office/display room we did have a lion fish.
It would follow you as you moved through the room.
Also, this is about the fish.
Livingston was portrayed by a red lionfish (Pterois volitans) in nearly every appearance. Only in “Devil’s Due” did the fish change species and appear as a radial firefish (Pterois radiata).
The Star Trek Encyclopedia describes the lonely exotic fish in Picard’s ready room, named for TNG and DS9 producer David Livingston, as an Australian lionfish. There are several species of lionfish, more precisely in the genus of pterois, and on close-ups it becomes apparent that Livingston must be a red lionfish (pterois volitans). The red lionfish is overall ochre with dark brown stripes. The fins and spikes are partially fasciated. Beginning with TNG: “Encounter at Farpoint” Livingston appears a couple of times in almost all seasons of TNG until “Bloodlines” in the seventh season, and the species remains consistent.
There is only one clearly visible exception, ironically in the episode which shows the best close-up of the aquarium. In TNG: “Devil’s Due” (fourth season) Livingston is a radial firefish (pterois radiata), another species of lionfish. This species (which is rather red than the so named lionfish) is overall darker and more colorful and is lacking the characteristic stripes, especially on the fins. It seems that after not appearing for two years the old Livingston was not available any longer by the fourth season (although the lifespan of the species is more than ten years) and a stand-in was needed. By the fifth season the Art Department may have found another member of the correct species