Honestly yes, but that’s true of anything. A rabbit can die from hearing a frying pan fall on the floor, or from an owner spooking it in the dark. A rabbit can die by choking on pellets…. Rabbits are pretty fragile, which is scary, but that’s why it’s important to dedicate time to upkeep and not cut corners on their sanitation and needs. The algae could have attracted parasites that are now in her body. The algae could have formed and developed mold which is now in her body. There could be ill effects to her mouth region from the exposure. There’s a lot that could happen, or nothing could happen.
The bottom line is you’ve identified a problem and you know how to prevent it from happening again, so improve the water dish routine and monitor your rabbit for ill health signs to see if the algae has made her sick. Monitoring rabbit behavior for sign of ill health is a primary, daily responsibility of all owner. Teeth grinding in pain, lethargy, lack of appetite, not pooping, becoming very aggressive to touching (because she’s in pain), consistently being in a hunched position, small poops, peeing on her self, leaving pee spots where she sits…there’s a lot of signs a rabbit can use to express ill health. So pay attention and if you see any bad signs, visit a rabbit experienced vet.
If she is going to get ill, she’ll show signs, whether they be subtle or dramatic. If she continues to have healthy poops, activity, peeing, and general composure, than it probably didn’t harm her this time, but be sure not to let it happen again.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.