The ornamental design for a tray for a shower caddy, as shown and described.
FIG. 1 is a front-left perspective view of a tray for a shower caddy of the claimed design;
FIG. 2 is a front view of the tray for a shower caddy of FIG. 1;
FIG. 3 is a rear view of the tray for a shower caddy of FIG. 1;
FIG. 4 is a bottom view of the tray for a shower caddy of FIG. 1;
FIG. 5 is a top view of the tray for a shower caddy of FIG. 1;
FIG. 6 is a left side view of the tray for a shower caddy of FIG. 1;
FIG. 7 is a right side view of the tray for a shower caddy of FIG. 1; and,
FIG. 8 is a front-left perspective view of the tray for a shower caddy.
The evenly spaced broken lines shown in the figures represent portions of the tray for a shower caddy that form no part of the claimed design and the dot dash broken lines show environment.