| No. | All keepers listed by when they started keeping this species. The longest an individual has been kept is 3 years, 8 months. |
| 1 | Brooklamprey (k: 13) since 2005-09-13 to 2009-05-22, that's 3 years, 8 months; who writes, "These fish have been observed feeding on dead fish and fillet as well as frozen thawed fish." |
| 2 | Silurus since 2007-03-11 to 2009-03-11, that's 2 years, 0 months |
| 3 | Attu since 2007-04-27 to 2009-04-27, that's 2 years, 0 months |
| 4 | Emuz-Atik since 2011-02-06 to 2013-02-06, that's 2 years, 0 months |
