דגי הקופסא מתאפיינים בגדלים שונים ומתחלקת למספר משפחות קטנות ,
דגים אלו אוהבים מזון בשרי והם נחשבים כטורפים ברובם , דגי הקופסא אוהבים מקומות מסתור רבים .
דגים אלו מסוגלים להרחיב את גופם פי 3 כאשר את נבהלים בדרך כלל הם ממלאים את גופם במים ונראים כמו כדור/בלון .
דגי הקופסא לא מתאפיינים בצבעוניות יתרה אבל הם מפצים על כך באופי שלהם.
דגים אלו בעלי שיניים ולסת מיוחדת אשר עוזרת להם לפצח מזון קשה וקונכיות סרטנים למינהם.
דגים אלו יכולים להגיע לגדלים של 8-10 ס"מ וישנם כאלו שיכולים להגיע גם לגדלים של 2 מטרים.
דגים אלו צריכים מים נקיים ודורשים החלפות מים תקופתיות כמו שאר הדגים
דגים אלו בחלקם מאוד אגרסיביים כלפי דגים מאותה משפחה וגם כלפי משפחות אחרות של דגים.
Most species of Puffers reach approximately eight inches in length with the exception of the Canthigaster Puffers, which reach an average size of only three inches. Puffers are relatively hardy and adapt well to captivity if provided with swimming room, a varied meaty diet, and a few hiding places.
Puffers are comical looking fish, especially when they are "puffed up” and look like a ball with fins. By rapidly swallowing water or air, they are able to expand their bodies up to 3 times their normal size in order to deter predators. Many species also have spines covering their body as added protection. Although most Puffers are not very colorful, they make up for it with their character and personality.
When kept in an aquarium, Puffers quickly adapt and recognize their owners and will always be "begging” for a meal. Puffers come from warmer ocean waters around the world where they feed mainly on crustaceans and mollusks. They have specialized teeth and powerful jaws that allow them to crush the hard shells of their prey.
Puffers vary in size – the smaller species only growing to 3 inches and the largest reaching over 2 feet in length.
Puffers are generally hardy and do best in large tanks with lots of swimming space and some rocky décor for shelter. Larger species definitely require an efficient filtration system along with frequent water changes to deal with the large amounts of food consumed and waste produced.
Puffers will eat all types of food and should be fed a variety of meaty foods such as shrimp, fish, clams, etc., along with a supplement of vegetable fare to provide necessary nutrients. It is also important to provide hard shelled crabs, mussels, and shellfish in their diet to wear down their teeth and prevent them from overgrowing.
Puffers are semi-aggressive and should be kept one per tank. They will eat smaller fishes and should not be housed with any delicate slow-moving species. Always remember to exercise caution when you put your hands in the aquarium - Puffers can deliver a nasty bite!
Puffers are very difficult to breed in captivity and there are no external differences between the sexes