Mute must put pets to sleep - no motion and closed eyes
Please consider motion sensitivity assessment for all aspects of gameplay, including pets. Pets previous to Kamigawa: Neon Dynasty generally go to sleep, eyes closed and motionless, when muted.
The new koi fish pets in Neon Dynasty do not. They continue to circle around and around when muted. Also, the koi fish flicker. Both of these visual behaviours are incredibly difficult to handle for people with motion sensitivity. The Pompon-chan pet doesn't close its eye or stop moving when muted, continuing to stare at you with glowing blue eyes.
Please make sure that pets go into a very low distraction mode when muted, otherwise players will just concede whenever a distracting pet is on the battlefield, which is not fair and is no fun for either player.