Triple fluorescence in situ hybridizations (ISH) and immunocytochemistry (ICC) for zecac mRNA/zpmca2 mRNA/Na+-K+-ATPase (A-E) and zecac mRNA/zncx1b mRNA/Na+-K+-ATPase (F-J) in frozen sections of zebrafish gills. A-E are the same section, and F-J are another section. A, zpmca2 mRNA; B and G, zecac mRNA; C and H, Na+-K+-ATPase (NKA); D and I, bright field (BF); E, merged image of A-D; J, merged image of F-I. Colocalization of the 3 transporter mRNAs and protein was found respectively in E and J. Scale bar = 20 μm.