Multiple tube in rock form

With tubes (two-sided openly) size 1 middle interior diameter very small ca. 1,9cm and ca. 8,5cm long (for Jungwelse)

With tubes (two-sided openly)
size 2 middle interior diameter very small ca. 2,7 cm and ca.10 cm long. (for small L- catfishes, e.g. L46, L174 and small peckoltia-types).

With tubes (two-sided openly)
size 3 middle interior diameter ca. 3,1 cm and ca.12 cm long (for middle L-Welse z.B.L201, L260, L270, L134, L181, L183 and larger Pekoltia-types)

With tubes (two-sided openly)
size 4 middle interior diameter ca. 3,7 cm and ca. 14 cm long (for larger Welse for example L66, L204, L333)