Finally got Level 6

Here's what I did (with 6 seconds to spare):

Buy 2 fish immediately
Drop 1 food
Send 1 egg to refinery and 1 to incubator
Collect 3 bears (selling 2, warehousing 1)
Feed the fish and buy 4 butter when the boat returns
Sell 1 bear
When the boat returns, buy 4 butter

Always send 1 egg to refinery and if you have 1 left, send 1 to incubator
Only incubate eggs up to a total of 7 fish swimming

Once you have your 7 fish, always sell buttered caviar, refined caviar, and a bear if you have one -- only leave 1 unprocessed egg in the warehouse.

Upgrade the boat as soon as possible after you've bought your 8 butter
Upgrade the mixing plant as soon as possible after that

At this point, always keep your water full, keep the boat going to market, and click
plants as much as possible

After the 8 buttered caviar are done, buy fish. You should have enough to buy 8.

Thanks for this.
Much appreciated.
Cheers.

Thank you very much for your strategy....

I was not able to do it with accurately your strategy....
I started as you, but I continued to incubate fish, even though it meant that I had to do the feeding somewhat more often....
- because then I could actually at one point buy two or three fish with my money, and finish off the fish goal sending them all in one load in my upgraded boat....
- that made it easier to concentrate on pushing the final buttered caviar and refined caviar through...
Without an upgraded warehouse though, I had little luck with the bears...

I cannot get gold on this level to save my life...UGH!

Thank you for your post; been at Level 6 forever. Cant wait to try your way. I was close but ... Im also stuck on Level 11. I have a Gold on all others so pretty frustrated I cant finish this game. Can you help with it? Much appreciated!