-- Last Updated: Mar-23-12 10:45 PM EST --
....... but I understand they'll take a bait on bobber . What size fish are you expecting to catch ??
In open waters where you don't have concerns of dealing with a fish running into cover like submerged brush , limbs , rocks , ect. , 4 lb. test has no problem dealing with a 4 lb. fish , 6 lb. handles a 6 lb. fish , 8 lb. test handles 8 lbs. and so on .
Remember that thing on a spin reel called "drag" , seems no matter what size line I'm using , it's a given one fish or the next will force me to loosen the drag more to save from break off .
I once brought a 42" river Muskie to boat side on 8 lb. test , and you know the drag got loosened for that one , which also means he had his way for a long , long time .
If I'm in a stumpy Bass lake with submerged trees , cover , etc. ... a 5 lb. Bass has a good chance of breaking 8 lb. line , lost too many that way so I keep a spool of 10 lb. at the ready .
Remember , you can always get extra spools for your spin reel and have different lb. test line on each ... I do it that way so I can just swap spools when I want to .
A 2500 series spin reel is a nice versatile size , it'll handle Bluegills as well as river Muskies and Walleye , so I reckon it's good for Trout too ... a 2000 series can do it well also . just remember , you got drag to compensate for lighter lines dealing with heavier fish .
I think there's even some kind of Andy tournament where they catch Marlin on 4 lb. test ...