The Lutefisk God can be offered Lutefisk by dropping lutefisk on a Lutefisk Statue.
Each time you tithe a lutefisk, you increase your odds of receiving a random artifact. For each 125 lutefisk, the artifact will have an additional enchantment (up to 500 lutefisk). When you receive an artifact the statue destroys itself and the tithe amount resets to 0.
The Mushroom Farmer of Fungal Arts is especially good for generating spores and transforming them by Horadric Lutefisk Cube into lutefisks. Each 32 rounds you gain additional spores, more Fungal Arts skill - more spores. The second skill in the Burglary skill tree, "Lucky Pick" also gives more items to be transformed at a rate of 3 per 45 turns. Also you can transform low level amunition, if needed. If you don't have either of those skills, buying all of the Softballs from every Throwing Vending Machine you can find will give you plenty of fodder for the Cube long before you get to a floor of the dungeon where Lutefisk Statues are worth using. It is not advised to waste your hard-earned Lutefisk on any floor before 5, as the item you get will probably be outdated very quickly.
The way that donating works is as follows:
Each donation gives you a random (and increasing) chance of getting a reward. The chance of receiving the reward on any given donation is <total accumulated donation>/500. So if you donate 250 at once, you have a 50% chance of receiving a reward. If you didn't get a reward at 250, and then you donate 10 more, you have a 260/500 chance of getting a reward.
The quality of the reward increases as follows:
- 125 donated -->> item scaled to the dungeon level
- 125 to 249 donated -->> same as the first + 1 random enchantment on the item
- 250 to 374 donated -->> +2 random enchantments
- 375 to 499 donated -->> + 3
- 500+ donated -->> + 4
Note that once you actually receive a reward, that your donation count goes back to zero. And also there's no benefit for donating more than 500 total (so if you are at 450, don't donate more than 50 -- save the rest for your next donation).
Also, keep in mind that since the base item that you will receive is tuned to the level of the dungeon of where you make your last donation, you may want to hold off on donating until later levels.