1. **State the problem:** We have 50 fish in total. Among them, 15 are tench. Of the remaining fish, 1/5 are minnows and the rest are goldfish. We need to find the ratio of tench to minnows to goldfish in simplest form. 2. **Identify the total number of fish that are not tench:** $$50 - 15 = 35$$ 3. **Calculate the number of minnows:** Since 1/5 of the non-tench fish are minnows, $$\frac{1}{5} \times 35 = 7$$ 4. **Calculate the number of goldfish:** The rest of the non-tench fish are goldfish, $$35 - 7 = 28$$ 5. **Write the ratio of tench to minnows to goldfish:** $$15 : 7 : 28$$ 6. **Simplify the ratio if possible:** The numbers 15, 7, and 28 have no common divisor other than 1, so the ratio is already in simplest form. **Final answer:** $$15 : 7 : 28$$