Sometimes called the Pantanal of Argentina, Esteros del Ibera is in Corrientes. This is a wonderful place to see all sorts of crazy animals. Kayman (similar to Alligator / Crocodiles), Capybara (worlds largest rodent ~300 lbs), and Anaconda's (big snake) all call this area home. The area is basically a very alkaline shallow water area. There are "islands" in the water area that are just floating plantlife.
Puerto Valle - Hotel de Esteros, 3302 Esteros del Iberá (Ruta Nacional 12 km 1282), ☎ +54 3786 425 700, . from 210 USD. edit
Irupe Lodge (Eco Lodge Ibera), Laguna Ibera (calle Yacare e Ysipo), ☎ +543752438312, . checkin: 12 am; checkout: 10 am. Small and exclusive eco lodge right at the lake Ibera side in the middle of the Esteros del Ibera. 9 original rooms in modern-rustic style with lake view. The offer goes from transportation to/from, excursions into the wetlands (boat safaris, night safaris, trekking, horse riding), restaurant, pool at lake side and authentic days with the gauchos. Special packages all inclusive with or without Iguazu Falls.90-140. edit
Estancia Don Joaquin (Ecolodge Corrientes), Route 12 km 695, ☎ +549111554667805, . Typical and luxury Argentine ranch,horse ridings activities,gaucho activities and typical Argentine dishes:asados and homemade food.11 rooms.This ecolodge offers taylor-made and all inclusive programs. U$140. edit