Nearly 1600 ha of habitat have been restored at 300 floodplain sites of the Middle Rio Grande (MRG), New Mexico, USA, as part of a cooperative effort of the Middle Rio Grande Endangered Species Collaborative Program to conserve the endangered Rio Grande silvery minnow (RGSM). These riverside sites are designed to inundate during spring run‐off and create ephemeral habitats for other aquatic and riparian species. This study of four restored floodplain sites in May–June 2017 found that of 14 fish species captured with fyke nets, common carp (41%), red shiner (32%), RGSM (16%) and white sucker (9%) dominated total numbers. Adult RGSM included 42% gravid females, 36% ripe males and 22% spent females, suggesting that this endangered species was spawning in and near these floodplains. Larval sampling also showed that restored sites and adjacent mainstem banklines were being used as nursery habitats, where RGSM larvae dominated six and nine species with 80% and 74% of total numbers, respectively. System‐wide proportions of RGSM larvae by phase suggest that larvae leave the floodplains and move to mainstem banklines beginning as late mesolarvae and metalarvae (14–22 days post‐hatch), and most depart by the juvenile stage. Altogether, 15 fish species were encountered in restored floodplain sites in 2017, compared to 16 species reported in concurrent annual mainstem monitoring. This study and others show that most fish species of the MRG move onto restored and natural floodplains equally in spring, and many use these habitats for spawning and as larval nurseries.

Praziquantel, an anthelmintic, is commonly used to control the Asian fish tapeworm Bothriocephalus acheilognathi in grass carp Ctenopharyngodon idella and baitfish. We treated 50 individuals from three different cyprinid fish species with praziquantel at 6 mg/L, a dose higher than the minimum recommended for complete Asian tapeworm removal in 24 h but much less than the concentration that would have ill effects on the fish. Praziquantel killed hundreds of adult tapeworms, but many ruptured and released eggs. We observed that the eggs released from Asian tapeworms treated with praziquantel were viable and produced thousands of coracidia over several days. We warn fishery managers that even if fish receive the typically recommended praziquantel treatment regime and all adult tapeworms are killed, viable eggs and coracidia may be present in the holding water or attached to the skin of treated fish, the surfaces of equipment, or treatment personnel.

Yaqui topminnow Poeciliopsis occidentalis sonoriensis and Yaqui chub Gila purpurea, two federally endangered fishes from the Rio Yaqui basin (Arizona, USA, and Sonora, Mexico), were propagated by various methods. Propagation of Yaqui topminnow was attempted in aquaria and wading pools; the greatest number of offspring was produced in 556‐L, plastic wading pools. We added substrate, artificial plants, and a vertical mesh barrier to create refuge for offspring. Fish were stocked when water was 19°C; after 1 month, when water temperatures exceeded 21°C, Yaqui topminnow started to produce young continuously. On average, 7.4 offspring/d were captured from four pools collectively. Yaqui chub were propagated in 189‐L, glass aquaria. We manipulated photoperiod, diet, and substrate to induce spawning of Yaqui chub, but success was only achieved after the water was chilled to 17°C for 30 d and then adjusted to 21°C over 14 d. After the water was maintained at 21°C for 3 d, we covered the bottom of each aquarium with glazed ceramic tiles and a raised plastic grid to protect eggs from predation. Broadcast spawning of Yaqui chub occurred at night; the next morning, we retrieved the tiles and the attached eggs and placed them in incubation tanks. Yaqui chub eggs hatched over the next 5 d, and the hatching success rate averaged 83%. After this initial spawn, manipulation of water temperature was not required to induce spawning, as Yaqui chub spawned each time tiles were placed in the tanks. These methods worked well, and we recommend them for propagation of Yaqui topminnow and Yaqui chub.