I have had void salmon and sturgeon both going but the void salmon got two days in a Rowe and the sturgeon I got nothing, both after 10 in-game days. I was wondering if this is normal.
On the wiki, there's a section that tells you what any given fish produces:
What you might've missed is the percent chance that anything will be produced:
The chance that a Fish Pond will produce an item starts with the equation
(0.15 + 0.08 * population of pond).
In other words, as the population of a pond ranges from 1 to 10 fish, the chance of producing anything ranges from 23% to 95%. There's always a 5% or greater chance the fish pond won't produce anything.
I'm not sure how many Sturgeon you have in your pond, but if you have fewer than 10, the chance of getting Sturgeon Roe is significantly lower. For example:
10 Sturgeon -> 95% chance of anything -> 25% chance of 2 Roe; 100% chance of 1 Roe
9 Sturgeon -> 87% chance of anything -> 80% chance of 1 Roe
8 Sturgeon -> 79% chance of anything -> 60% chance of 1 Roe
7 Sturgeon -> 72% chance of anything -> 60% chance of 1 Roe
These are just the initial checks. The game proceeds through several levels of checking to produce an item, but the chances get lower at each level. We can sum up all the levels to calculate the full chance that 9 Sturgeon will produce a Sturgeon Roe. (Notice how each level starts with the % that the previous level didn't produce.)
87% * 80% = 69.6% 1 Roe
87% * 20% * 60% = 10.44% 1 Roe
87% * 20% * 40% * 40% = 2.784% 1 Roe
87% * 20% * 40% * 60% * 20% = 0.8352% 1 Roe
69.6 + 10.44 + 2.784 + 0.8352 = 83.6592% chance of 1 Roe with 9 Sturgeon
Similar math can be done for other numbers of Sturgeon.
Now if you only have, say, one Sturgeon, then the math is:
0.23 * 0.2 = 0.046
That is, 23% chance of anything * 20% chance of 1 Roe = 4.6% chance of 1 Roe
So chances are you'd get 1 Sturgeon Roe in 22 days.
Now of course over time your Sturgeon will grow, as long as you keep fulfilling their requests, so the chance will increase. But the chance is a lot lower than you might think from the "20%" given on the wiki page, due to the initial chance that the Fish Pond will produce nothing at all at any level of fish.