I'm glad the information was useful for you, regarding your question, 1" per month is already fairly fast, but if you want to try to exceed that I would recommend using either bloodworms or earthworms as a staple/base food. Because your sturgeon is 6", earthworms would probably would best, however, I'm not sure if you can get them easily, for where I am, they're very difficult to find, the place I do get them they cost $5 for 12, and seeing as how my fish can eat several of them a day, it can get quite expensive. Going outside and digging would be the alternative, but not if the ground is frozen 70% of the year, and an extra special bug phobia adds to the fun. If you cannot easily get earthworms, then live or frozen bloodworms would be the alternative, live is almost always better, and I would strongly recommend staying away from freeze dried foods, it won't hurt the fish, but freeze dried foods often carry very little nutrients, with frozen you lose a bit of the health benefits, but you also are playing it safe, since not all live foods are bred/raised in the most sanitary conditions, which could transfer harmful diseases and parasites to your fish, freezing them would normally kill anything that could harm your fish. Adding to this, when I'm talking about using frozen, I'm not referring to earthworms, live earthworms are best to use, if you're not exactly sure where they're coming from or how they're raised, it would be a good idea to keep them in oatmeal for 12-24 hours which will clean out their systems and get rid of the dirt they've been consuming in the event there could be any foreign things you don't want transferred to your fish.
As well as your base diet of earthworms it's good to have a variety, switching what you're feeding every day, week, fortnight or month, with earthworms being your base, you would never change that, since they tend to be very nutritious and can help speed up the growth rate, but as said earlier, make sure you know where they're coming from, if you don't, then definitely use the oatmeal method. I would say have at least two other foods that you're feeding your sturgeon, not including your staple. The best things to use IMO, chopped tilapia (this one is a hit or miss, some fish love it, some have no interest), chopped prawns, chopped shrimp, large mysis shrimp, mussels (my big guys love this, especially my eels and catfish), oysters (again, it's a hit or miss), silver sides (might want to water this one, many stores sell smelt in place of silver sides, just make sure you know what you're feeding, all my fish eat them, the gars seem to favor them the most), salmon roe is a great choice as well, it can sometimes be a bit expensive, but it's very nutritious, and would aid in helping the growth. Another good food would be clams, I would actually recommend going to an Asian market, they normally have a large variety of sea foods, and a lot of the frozen foods aquarium stores have, Asian markets will have them too, often a larger amount for much less than what you'd pay at an aquarium store. I used to spend up to $200 on fish food, but now, getting 80% of their food from there I'm now paying a fraction of that. It's very important to check the ingredients and look at the packaging, there have been a few times I've bought seasoned food, or cooked and only noticed when I'm preparing everything for the month. Sometimes it can be difficult to find foods that aren't seasoned with salt, so it's good to just rinse it with cool water for at least 30 seconds.
Personally, I'm a bit (a lot) of a control freak, so I like to have lists and schedules for just about everything, I've found using them for my fish keeping is quite helpful. I normally go out, buy a bunch of food, some fresh, some frozen, get out some freezer bags, and label them for each tank, "Monsters" "Cichlids" "Axolotls" (next month I'll be doing one for my grow outs, I used to have a couple, but shut a bunch of my tanks done, just last week started a couple up again
), cut everything up, putting the staple/base food in every bag, then having a randomized order for the rest of the foods, then once I'm done, close all the bags, and put them in the freezer. Having them prepared for the month makes things a lot easier, it normally takes four hours to get everything ready, but then for the next little while all I need to do is take a bag out for each tank, put it in water, rinse it and feed. Rather than the alternative of getting out 15 different things every morning, sorting through it, cutting it up, ect. It can get to be a bit of a hassle. So, if you were to do a similar thing; because earthworms are your staple, you wouldn't freeze or cut them up until you're ready to feed them to your fish, so you'd leave those out, what you could do is have 30 bags, each with enough food for 3 or 4 feedings-have salmon roe, silversides and mussels in 7 of the bags, tilapia, clams and prawns in another 7, and so on. And with each feeding you'd give maybe half or a whole earthworm, it would also be great if you could find a good pellet food that your sturgeon will eat as well, and you could feed that daily. If you're feeding four times a day, then spread it out to every 6 hours or so. You could make pellets the first food you feed in the mornings, that way it's not a huge rush to wake up and thaw the food right away, just drop some pellets in, and you're done.
And, as with any grow out tank, it's important to keep up on water changes, if you don't ammonia, nitrite and nitrate will build up and possibly stunt, or slow down the growth quite a bit. I would recommend keeping it in a bare bottom tank so waste is easier to siphon out. It's also important to not let food sit in the aquarium for more than an hour, after that you'll want to net it out. I would recommend doing a water change at least twice a week, and having good filtration will help a lot with keeping the aquarium clean. Just remember, the more you feed, and the better the water quality, the faster your little guy will grow.
As a side note; Live black worms can be an alternative to feeding earthworms, however, personally, I won't feed them to my fish more often than once a month because of how they are bred. There was a time I did have a black worm culture, and when I bred them myself I wasn't worried about foreign bacteria, however, when buying them from stores it can be a bit of a gamble, I would say unless you're breeding them yourself, I wouldn't feed them regularly. There is a lot of debate around feeding live black worms, but my opinion on it, unless you're buying them straight from the source, you know that they're being kept in absolutely excellent conditions, or you're breeding them your self, I wouldn't even bother with feeding them.
