My fish won't eat after traveling. Is it stress, new food, or water?

Most puffers will not eat flakes or pellets. They need live or frozen foods. They also require hard foods to keep their teeth worn down. The local Petco will likely have these foods in stock. If the tank is overstocked, he may be stressed. He may also have an infection (bacterial, fungal or parasites) that are causing his symptoms. Ideally, a new fish should be quarantined for 2-4 weeks before being introduced to the main tank.

This is a quite generic but concerning presentation. Begin by submitting a water sample for quality testing. Most pet stores will do this for free or a nominal fee. Clinical examination should always include a water quality check, even if you have done so already. Water testing should be performed with a quality test kit, measuring NH4, NO2 and NO3. High ammonia levels, PH imbalances may be responsible for these signs. Oxygen concentration and quality of the filters should be determined as well. If water quality is good and there are no major imbalances, your fish should get examined to look for any sign of bacterial/fungal infection and eventually water should be treated. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

Anytime you transport a fish, it can be stressful. Loud noises, vibrations and no filtration can cause stress. Check the water chemistry using a liquid home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20 ppm or less. Perform a partial water change if indicated. Use only conditioned water that is temperature matched to prevent further stress or shock.

There are a few possibilities including normal adjustment or something wrong with the water quality. Also, you will need a bigger tank for Nutty that includes a filtration system. Here is a link about goldfish care: https://www.petcoach.co/article/how-to-help-your-new-goldfish-thrive/ https://www.aqueon.com/information/care-sheets/goldfish Make sure the water quality is good for Nutty. I hope this helps and please feel free to post any additional questions.

An immediate veterinary check up is needed. Fish may have got spiky bones in it, or may have been not in good hygiene status. Considering his age and the signs you are describing an examination is necessary to shed some light on the underlying cause of it. Antibiotics and nutritional support may be needed as well.

Check the water chemistry. A large water change can cause ammonia spikes or other imbalances. Check the water temperature as well. Goldfish do best in cooler water, between 65 F and 72 F. Consider a quarantine tank for him if he is the only symptomatic fish. Continue with the medications as directed on the package.

Thanks for reaching out. Sounds like new tank syndrome, which is the time it takes for the biological filter to come up to speed, reducing ammonia to nitrites to nitrates. Continue to test and perform water changes as needed, giving the filter time to establish. Good luck.