Tetra’s innovative new gel feeder blocks contains no plaster and feed up to 14 days with the Tetra Vacation 1.06oz. Blended with patented ProCare for optimal health. Tetra’s feeders provide real nutrition to fish when they need it. Allows fish to eat when hungry vs. plaster feeders that dissolve. Packed with Tetra’s patented, health enhancing ProCare ingredients. Will not pollute water or negatively effect water quality. Gel blocks may be left in the aquarium when regular feeding is resumed.