Ah, I just noticed the part in the journal that says something about most money made from a fish... My bad. It's $7,303 for a Deathfish.

I was probably looking at the lousy 5k fishes among the 300 fishes I had in the mummy's inventory (which totaled $1.5mil). Crap. Now I have nearly 6 mil again.
Did it seem like the values of the Deathfish steadily rose as you kept on fishing over a period of time?
Yes, it rose steadily. The average increases over time. What I meant when I said I don't know what the factors are is whether
time increases the value of Deathfish or its
bait(my bait is always Perfect, though the weight of Angelfish constantly rises when I fish them) or the
number of fish fished.
I believe that the full quality of any fish is retained with the Omni Plant. It's fruits and vegetables that lose quality in the clones.
I can confirm that... That Deathfish is harvested at the exact same quality, weight and price from Omni Plants. No higher, no lower in value.