Crisp heads of emerald romaine, pale oak leaf, along with bags of red and green butter lettuces greeted the customers at the indoor market last Saturday. Really fresh lettuce in wintertime is a dream come true for salad aficionados in northern Colorado, and it’s coming from a greenhouse smack dab in the middle of neighboring Laporte. Grown in an aquaponic system—not hydraponic, which relies on inorganic chemical fertilizers, and not aquaculture, which is a fish farming method that often pollutes downstream waters—the lettuces and herbs from Quatrix Ltd. are grown organically and are of very high quality. The system combines tilapia farming with vegetable production in a symbiotic relationship that is completely eco-friendly.
Five separate tanks holding 1000 fish each are the first stage of the closed-loop system at Quatrix. Instead of releasing the waste-filled water to prevent the buildup of toxins in the fish, the water is treated with bacteria to convert the ammonia waste into nitrates, preferred by plants as food. Grown in floating rafts on the treated water, lettuces and herbs (and earlier, tomato and pepper plants) are nourished by the treated nutrient-dense fish water. The plants, in turn, filter the water so that it can be returned to the fish tanks 97% free of nitrogen, producing fish that taste clean and fresh, with no off flavors often found in farmed fish due to toxic buildup in tissues.
While the tilapia is not yet available, the vegetables are ready for purchase at the indoor market and at the Food Co-op on East Mountain Ave. Look for the tilapia this summer at the farmers markets, and hopefully, at other retail outlets. In the meantime, practice using tilapia with the easy and quick recipes for this mild white fish:
Tilapia with Prosciutto and Sage
One tilapia fillet per person
1 very thin slice of Prosciutto per fish fillet (substitute bacon slice)
2 fresh sage leaves per fillet
Wrap each fillet, thawed, with the Prosciutto, tucking one or two fresh sage leaves in between the fish and the Prosciutto. Pan fry about 4 minutes on the first side, and 3 minutes on the second side, and serve immediately.
Quick Lemon-Curry Tilapia with Cucumber Salad
¾ cup plain yogurt, whole milk
1 cucumber, halved lengthwise, seeded and cut into half-moons
1 large carrot, peeled and grated
juice of 1 lemon, divided
salt and pepper to taste
Optional: torn mint leaves added at the very last minute
2 tbsp. coconut oil
4 tilapia fillets
1 tsp. sweet smoked paprika
½ -1 tsp. curry powder
1-2 green onions, chopped fine
Combine the yogurt, cucumber, carrot, 1 tbsp. lemon juice and salt and pepper. Set aside.
Heat oil in a large skillet. Season the fish with salt and pepper and paprika, plus the curry powder. Place in hot oil and cook about 5 minutes per side, until opaque. Turn only once. Drizzle with remaining lemon juice and serve with cucumber salad, topping both with green onions.