Per minute sounds pretty good.
Memory Siphon (Su): An aboleth consumes the memories of any living creature it ingests. Any living creature in the aboleth’s esophagus immediately, and every minute thereafter, gains one negative level. In addition, whenever a creature gains a negative level it must succeed a Fort save (DC 18) or take 1 INT and 1 WIS drain. The DC is 18 for the Fortitude save to remove a negative level. The save DC is Charisma-based.
Memory Siphon (Su): An aboleth consumes the memories of any creature it ingests. Any creature the aboleth consumes must succeed a Fort save (DC 18) or have its memories siphoned as though by a mindwipe psionic power (ML 10th, 2 negative levels*), except that negative levels gained in this way are permanent. The save DC is Charisma-based.
Servitor Transformation (Su): To prepare an enslaved humanoid or monstrous humanoid for long-term servitude, an aboleth encases the creature underwater in a thick slime cocoon. This cocoon is identical to the nourishing shell that aboleth lay their eggs. However, a living creature encased in it is transformed into a subservient aquatic creature (see Aboleth Servitor template) over the next 1d4+3 days. During this transformation, the target creature is not only physically changed, but mentally changed to be completely subservient and pliable to the aboleth's whims, including transfer of control to another aboleth.
A target creature is still afforded any Will saves it is allowed to break the aboleth's control (at a -4 penalty) during the first 3 days of the transformation. Any target able to regain autonomy may attempt a DC 10 Strength check (each retry at a +1 DC) to escape the slime cocoon. A creature that is able to escape can be restored to normal by a heal or greater restoration spell.
If after 3 days the creature is unable to escape, it is rendered completely immobile as the transformation runs its course. Once transformed, the creature is bound indefinitely as a slave to the aboleth and is unable to further resist its control, barring death of the controlling aboleth or the use of a break enchantment or dispel magic spell against an effective caster level equal to transforming aboleths manifester level.
The physical transformation, once complete, can only be reversed using either a wish spell or similar effect.
You know, I'm not so sure they would have evolved that. But it would be one of the first things that an aboleth would pick up as a psion! Just my 2 cents, anyway.
Naturally Psionic (Ex): Empty vessels gain 1 extra power point per character level, regardless of whether they choose a psionic class.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.