It takes a child up to 21 exposures to a food before they will decide whether they actually like it or not. Children's tastes change constantly. In addition texture, the way a food is prepared, how it is seasoned, and how it smells are also big factors. Something they love this week they may hate next week. What they like at 18 months old they may not at 2yrs but enjoy again at 2.5 yrs old.
I would be very cautious about offering fish to an infant even a toddler...even fish sticks can have bones.
Kids will generally eat what parents eat. If they see you enjoying a healthy, balanced meal, and a variety of food, chances are they will be more open to trying it too. Offer what you prepare for meals, do not turn in to a short order cook.