The streamer test   fly fishing
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When fishing for tuna it is key have streamers that are 100% reliable. In some cases the feeding frenzy can last less than a minute and the last thing one wants is to have a fly that does not perform. Or even worse, a streamer that becomes a mess after the first cast.
Considering the amount of fry, I deem cautious to attach the streamer to a 25 cm. titanium trace. One never knows who might be prowling in the surroundings with this plenitude of minnows.