Go fish!

0 Hi everyone, 02br
00I found this expression regarding a guessing game. 02br
00A: Do you have an animal with tusks? 02br
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00B: Yes, I do. (No, I don't. Go fish.) 02br
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00A: Is it a walrus? 02br
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00B: Yes, it is. (No, it isn't. Go fish.) 02br
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00Don't tell me that it means to try the fish cards! So, does it mean to guess something else? 02br
00Thanks in advance, 0-