Okay. I was on earlier and will be on throughout the day.  I'll probably be on around 7-9 pm central US.  I assume you have all fruit and don't really need anything.

Ya I'm good now, Cerebral hooked me up, thanks though! I'll be jumping on after I get some food.

Finally caught a damn sturgeon. Only need stringfish and my March catch list is complete.

Also stumbled across an oarfish so I was able to run around showing it off like Etecoon.

Sorry I was on early and then now late in day.  I'll be around tomorrow though.  I actually sent eshop gift card to friend so he could buy it for his girl today.  I was busy earlier trying to help him out then I passed out apparently.  He seemed to be liking the game himself even though it was supposed to be gift mainly for his girlfriend.  I'm sure we will meet up sometime this weekend.

Yikes now you got me worried about missing them out in March...  I usually just ocean fish more because red snappers and knifejaws but I need to get stringfish and sturgeon.  Early morning/late night river fish right?

Still 4 days left counting today, you got time! Stringfish can be found in cliff rivers 4pm - 9am, Sturgeon are where the river meets the ocean and available all day. The wiki has been a good source: https://animalcrossing.fandom.com/wiki/Fish_(New_Horizons)

Only go for the biggest fish shadow. Run back and forth to scare the small and medium shadows away. Some islands tours have really good fishing. You'll occasionally get a pond or river with tons of valuable fish. Way better odds when you do. 

Sturgeon are any time of day, any weather, right now. River mouth.

Stringfish are 1600 (4pm) to 0900 (9am). Clifftop (aka, anywhere above a waterfall).

One of the best ways to catch either of them:

(1) Find a Mystery Island with a river & a waterfall.

(2) Run around scaring away all the other freshwater fish until you see either of these guys spawn.

(3) Catch em.

This works so well because there's a limited number of fish that can spawn at any given time. So, on a Mystery Island, since you have a much smaller region to work with, you can repeatedly force spawns in certain areas, making it easy to cause rare fish to spawn.

Few tips:
(1) Play in handheld mode. The input lag playing docked makes it a LOT harder to catch them, and rare fish seem to be more volatile to catch.

(2) Both stringfish and sturgeon have the largest shadow size. You'll know it's them when you see a rather large shadow. If it's not a BIG shadow, scare it off, try to get another one to spawn in that area.

(3) Sturgeon ALWAYS spawn in the part of the river mouth RIGHT where it transitions to ocean. See pink box:

If it looks big but isn't in this spot, chase it off. Probably just a black bass.

(4) This technique works BEST for sturgeon and ocean fish. Doesn't seem to work quite as well for stringfish, BUT that's not to say it DOESN'T work. However, if you're having trouble, another method can be to just toss fish food and keep going until you get em.

Thanks for the tips.  I plan on making the second post in op into a strategy guide or at the very least list all the insect/fish time of appearance in day, months, and value.  Perhaps I'll try and post a few other tips either from sites or my own.  Here is something semi funny.  I fish better by casting it and seeing the fish start to go for lure.  I then close my eyes and wait for the louder lure bob sound rather than look.  For some reason looking at the fish nibble the lure over and over again gets to me and I'm likely to hit button on a nibble.  I also mess up more often when I'm sleepy lol...  So I just make sure the fish is going for it then I have to close my eyes and wait for the main sound.

Yeah that's the best way to fish. Ignore visual cues - go with audio only. And that's another reason why handheld works better than docked - the sound gets to your ears sliiiiiiightly faster.