Watermelon

Russian Tortoise

Agrionemys horsfieldii

Very high water content combined with sugar makes it a poor dietary choice. Diarrhea risk if fed regularly; fine as a very occasional hydration boost in hot weather.

Sulcata Tortoise

Centrochelys sulcata

Very high water and sugar — diarrhea risk and inappropriate for a dry-land grazer.

Eastern Box Turtle

Terrapene carolina

[confidence: high] [source: Reptifiles box turtle care; VCA animal diet guides] Very high water and sugar content; excessive amounts can cause diarrhea; acceptable rare treat.

Greek Tortoise

Testudo graeca

[confidence: high] [source: The Tortoise Table; Tortoise Trust Mediterranean tortoise diet] Very high water and sugar content; completely inappropriate for strict Mediterranean herbivore that requires dry, high-fiber diet.

Hermann's Tortoise

Testudo hermanni

[confidence: high] [source: The Tortoise Table; Tortoise Trust Mediterranean tortoise diet] Very high water and sugar content; completely inappropriate for Mediterranean herbivore requiring dry high-fiber diet.

Leopard Tortoise

Stigmochelys pardalis

[confidence: high] [source: Reptifiles leopard tortoise care] Very high water and sugar; completely inappropriate for African grazing tortoise requiring dry, high-fiber grass diet.

Red-footed Tortoise

Chelonoidis carbonarius

[confidence: high] [source: Reptifiles red-footed tortoise care guide] High water and sugar content; acceptable occasional treat for red-footed tortoises as part of fruit portion of diet.